EMC DL3D Best Practices Planning

Transcription

1 Best Practices Planning Abstract This white paper is a compilation of specific configuration and best practices information for the EMC DL3D 4000 for its use in SAN environments as well as the use of its optional features. November 2008

2 Copyright 2008 EMC Corporation. All rights reserved. EMC believes the information in this publication is accurate as of its publication date. The information is subject to change without notice. THE INFORMATION IN THIS PUBLICATION IS PROVIDED AS IS. EMC CORPORATION MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WITH RESPECT TO THE INFORMATION IN THIS PUBLICATION, AND SPECIFICALLY DISCLAIMS IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Use, copying, and distribution of any EMC software described in this publication requires an applicable software license. For the most up-to-date listing of EMC product names, see EMC Corporation Trademarks on EMC.com All other trademarks used herein are the property of their respective owners. Part Number h5895 Best Practices Planning 2

3 Table of Contents Executive summary...4 Introduction...4 Audience... 4 Terminology... 4 DL3D 4000 overview...6 Supported environments... 7 Physical connectivity... 7 EDL-3D 4000 interconnections... 7 EDL flex ports D 4000 Ethernet connectivity Sizing the DL3D Data de-duplication...13 The process Key factors affecting the de-duplication ratio Configuring and using the DL3D D/3DR-enabled libraries and tapes Migration Reclamation EDL features impacted by 3D Copying to or from physical tape through the EDL s import/export feature Remote copy Using consolidated media management Tape shredding Active engine failover (AEF) Upgrading Replication...21 Overview Additional configuration requirements Initial setup Performing a replication Checkpointing Target side recovery Detecting replicated tapes on the target DL3D Direct-linked tapes Copy mode imports Performance impacts Configuring 3D 4000-specific operations...27 Performing a replication checkpoint operation On-demand replication checkpoint Scheduled replication checkpoint Failback of replicated tapes D 4000 space reclamation...31 Conclusion...33 References...33 Best Practices Planning 3

4 Executive summary Today s IT environments are faced with the combination of data growth and shrinking backup windows. Restore time objectives (RTOs) and restore point objectives (RPOs) are also becoming more stringent, increasing the importance of a highly reliable, high-performance backup environment. As a complement to tape for long-term, offsite storage, backup-to-disk and the EMC DL3D products have emerged as powerful solutions. For users interested in improving the performance and availability of their backup environments without changing their applications or infrastructure, the DL3D 4000 provides simple and reliable disk-based backup and recovery systems with the added feature of de-duplication. The DL3D products integrate seamlessly into your current backup environments. The DL3D 4000 was designed and implemented for optimal performance and ease of use, and easily scales to meet your storage needs. Introduction This white paper details the, highlights its advantages, provides an overview of its features, and provides specific best practices and tuning recommendations. Audience This white paper is intended for EMC system engineers and members of the EMC and partners professional services community who are interested in incorporating the DL3D 4000 into the backup environment. Terminology 3D An optional EDL feature that allows data to be migrated from native format on the EDL to deduplicated format on the 3D 4000 using significantly less capacity.. 3DR A licensable option of 3D with replication to another DL3D 4000 for added protection and recovery capabilities. ACSLS Automated Cartridge System Library Software. A centralized library management solution for use with StorageTek TLUs. Active engine failover The failing over of virtual tape library resources from one server to another. The DL4200/DL4206 and DL4400/DL4406 models are active engine failover (AEF) capable. Also referred to as failover. Array port Fibre Channel (FC) ports on EDL and 3D 4000 servers that are used to connect to the EMC storage array. These ports are sometimes also referred to as initiator ports. Backup-to-disk (B2D) A backup solution where data is written to hard disk instead of tape. Capacity optimized libraries 3D-, 3DR-, or Tape Cache-enabled virtual tape libraries. This is a licensable option that allows data to be temporarily stored on the EDL and later written to another system (3D 4000 or physical tape library, respectively), allowing space to be freed up on the EDL. Checkpointing Replication of metadata representing a tape s contents on the source 3D 4000 to the target 3D 4000 indicating that the copy of a replicated tape is complete. Data pool De-duplicated data stored on the 3D 4000 back-end storage array. De-duplication Process of detecting and identifying the redundant variable-length blocks (or data segments) within a given set of data to eliminate redundancy. DL3D Disk Library Data De-duplication. EDL EMC Disk Library. For the DL3D 4000, the DL4000 series models are the DL4100, DL4106, DL4200, DL4206, DL4400, and DL4406. Embedded Media Server A feature available on the EDL providing Symantec NetBackup media server functionality embedded within the EDL engine. This allows for NetBackup environment awareness of duplicate copies of virtual tapes that are exported to a physical library connected to the back end of an EDL and controlled by the embedded media server. Best Practices Planning 4

5 Embedded Storage Node A feature available on the EDL providing NetWorker storage node functionality embedded within the EDL engine. This allows for NetWorker environment awareness of clone copies of virtual tapes that are exported to a physical library connected to the back end of an EDL and controlled by the embedded storage node. Engine An EDL or 3D 4000 server. Also known as a server. Failover See Active Engine Failover (AEF). Flex port Fibre Channel (FC) ports on the EDL server that can be configured as either front-end (SAN client) ports or back-end (physical library) ports. Flex ports do not connect to the EMC storage arrays. See also library port. Hardware compression A hardware compression acceleration component that allows the EDL and 3D 4000 engine to dedicate more central processing power to other tasks while the hardware compression hardware accelerates compressed I/O throughput. Immediate de-duplication Process of de-duplicating the backup data stream as it is ingested by the 3D LDAP Lightweight Directory Access Protocol is an application protocol used for querying directory services running over TCP/IP. Allows customers to log in to the EDL using their corporate login and password. Library port Fibre Channel (FC) ports on the EDL server used to connect to a back-end physical library, another EDL, or a DL3D These ports are also referred to as initiator ports. Management IP address The IP address used by the EDL management console to access the EDL and for Remote Copy operations. Native format data Uncompressed and unde-duplicated backup data. Policy-based de-duplication The choice of immediate, scheduled, or no de-duplication. Remote backup A backup server writing across distance over FC to an EDL. Remote Copy An EDL feature that allows virtual tape cartridges to be copied from one EDL to another EDL over an IP network. Remote replication Backup data residing on a 3D 4000 is copied over a LAN or WAN to another 3D 4000 in de-duplicated form for disaster recovery protection. SAN client A backup server that connects through an FC SAN to an EDL. SAN client port FC ports on the EDL server used to connect backup servers (clients of the EDL). These ports are also referred to as target ports. Server An EDL or 3D 4000 server. Also known as an engine. Server grouping A configuration where the two EDL engines (in the case of a DL420x or DL440x) or two or more EDL appliances (for all models) comprise a group. The group is managed as a single EDL, but each engine services its own clients and virtual devices. Server grouping does not imply failover functionality. Source-based de-duplication De-duplication of backup data occurs at the client before it is sent to the primary storage system. Tape Caching Licensable option that allows data to be temporarily stored on the EDL. That data is eventually written to back-end physical tape, allowing space to be freed up on the EDL. Target-based de-duplication De-duplication of backup data occurs at the target storage system. TLU Tape library unit, sometimes referred to as a physical library unit (PLU). Virtual tape library (VTL) Software emulation of a physical tape library system. Best Practices Planning 5

6 DL3D 4000 overview The DL3D 4000 is a DL4000 series disk library with an attached 3D 4000 appliance, a disk-based deduplication backup option for EMC Disk Library (EDL). In the DL3D 4000, the data in EDL virtual tape cartridges migrates to the 3D 4000 where it is de-duplicated to remove data redundancies resulting in longer data retention capability than a stand-alone EDL as shown in Figure 1. Figure 1. DL3D 4000 data flow The 3D 4000 appliance with its data de-duplication capability: Eliminates redundant data from backups to reduce storage requirements, enabling longer onsite retention, and reduced replication costs Performs sub-file, variable block length de-duplication to capture small block inserts and overstrikes in unstructured data Understands backup software metadata to optimize de-duplication Includes built-in data compression that is additive to de-duplication in the data reduction process The 3D 4000 appliance s replication option leverages de-duplication, substantially reducing the amount of backup data that needs to be migrated to a remote site. 3D 4000 replication provides rapid local and remote restore with the following benefits: Permits bi-directional replication between 3D 4000 appliances Replicates de-duplicated virtual tapes to reduce bandwidth requirements Checks and validates each data block before replication so that only unique data blocks are sent to the target 3D 4000 to further reduce network traffic Maintains a common data de-duplication repository at the target 3D 4000 for maximum storage savings Provides optional 128-bit AES data encryption for replicated data Best Practices Planning 6

7 Supported environments The DL3D 4000 supports the backup applications and versions listed in the EMC Support Matrix on Powerlink for the EDL. Physical connectivity The DL4000 series disk libraries that support the 3D 4000 de-duplication option are the DL4100, DL4200, DL4400, DL4106, DL4206, or DL4406. These EDLs are comprised of one or more servers (engines) attached to one or more CLARiiON CX3-80 storage arrays depending on the model. The DL4000 series connects to the 3D 4000 via a dedicated DS-300B Fibre Channel switch through FC ports 4 and 8 on each EDL and 3D 4000 engine. The 3D 4000 is comprised of a 2U processing server (engine) with 32 GB of RAM, two hardware compression cards, four front-end 4 gigabit Fibre Channel ports, and eight Gigabit Ethernet ports attached to a CLARiiON CX3-40F storage array. The CX3-40F requires at least two DAEs and can be scaled up to 16 DAEs (148 TB). The storage array is specifically partitioned for use as a dedicated de-duplication appliance. EDL-3D 4000 interconnections There is a direct Fibre Channel connection between the EDL and the 3D The EDL engines connect to an FC switch that is an integral part of the 3D 4000 appliance. Ports 4 and 8 on the EDL engines and ports 4 and 8 on the 3D 4000 all connect to this switch. The switch is hard-zoned and only used for this purpose. It is not connected into the SAN environment. The following three figures show the FC port usage for the DL3D 4000 models. Best Practices Planning 7

8 Figure 2. DL410x-3D 4000 interconnection Best Practices Planning 8

9 Figure 3. DL420x-3D 4000 interconnection Best Practices Planning 9

10 Figure 4. DL440x-3D 4000 interconnection The 3D 4000 Fibre Channel ports 3 and 7 are unused. Do not connect these ports to any devices. EDL flex ports Each EDL engine has four Gigabit Fibre Channel flex ports (4, 5, 8, and 9) for target or initiator mode SCSI attach. Ports 4 and 8 must be used for connection to the 3D With DL420x and DL410x systems the remaining two ports, 5 and 9, are available for connecting a physical tape library or another EDL for use as a back-end library. With DL440x systems, ports 5 and 9 are required to connect the server to the other node s storage arrays. In order to connect a physical tape library or another EDL to a DL440x system, Best Practices Planning 10

11 one of the four front-end target ports must be converted to a back-end initiator port for use by the back-end device. 3D 4000 Ethernet connectivity A binding operation is performed between the EDL and 3D 4000 during installation. This binding establishes the network communication interface between the two systems. Changing the IP address of the 3D 4000 destroys this bind, preventing communication between the two systems. The 3D 4000 contains eight Gigabit Ethernet ports configured as a bonded network interface. All eight ports service replication traffic and appliance management traffic over the same bonded interface. The 3D 4000 manages the I/O distribution between the eight ports in an attempt to optimize the aggregate bandwidth possible across the links. Therefore careful planning and timing can optimize the performance of each particular operation through scheduling. When physically connecting 3D 4000 Ethernet ports to the network, connect all ports to be used from the 3D 4000 to the desired network switch(es). At a minimum, one Ethernet connection per 3D 4000 appliance is required for management and replication. More physical connections are recommended. The bonded Ethernet network interface in the 3D 4000 utilizes a balance-rr mode, also known as a round-robin algorithm for transmitting and receiving data to and from peer systems. This mode is hardcoded and is the optimal bonding mode for 3D 4000 operation; it cannot be modified. The underlying 3D 4000 appliance software and operating system manage the I/O distribution between each of the eight ports in an attempt to optimize the aggregate bandwidth possible across the links. These ports do not need to be connected to an intelligent Ethernet switch. In fact, no special configuration on the LAN or Ethernet switch end is required, allowing for maximum compatibility with the current Gigabit Ethernet environment already in place. Although the 3D 4000 can be connected to more than one Ethernet switch, all switch ports used for the 3D 4000 must be set up identically and each switch must be on the same subnet/vlan. When using intelligent Ethernet switches, significant performance optimization will be achieved through configuration settings on the Ethernet switch. Switches that support EtherChannel or, more generally, trunking or "link aggregation" can be configured to group the physical port connections to which the 3D 4000 is connected as a plain EtherChannel group and managed as a single connection with a greater theoretical maximum bandwidth. This aggregation of 3D 4000 port connections potentially improves replication performance depending on the environment. EMC prefers that a managed switch that supports these modes be used with the 3D Refer to the vendor documentation provided with your intelligent Ethernet switch for its specific configuration instructions. The 3D 4000 Ethernet network interface does not support LACP switch configurations. When connecting a 3D 4000 to the network, keep the following recommendations in mind: Use multiple 3D 4000 ports when connecting to the network. The more 3D 4000 ports used, the better the load balancing will be across the ports. For redundancy, connect at least two 3D 4000 ports to an Ethernet switch. Set each switch port used by the 3D 4000 to auto-negotiate/auto-sensing. The 3D 4000 network interface cards are preset to auto/auto and cannot be changed. Use a managed switch configured for "trunking" or "link aggregation" or "EtherChannel" to maximize replication performance potential. This can provide significant performance improvements. Use a dedicated backup network by configuring a separate network or use QoS features that help ensure network bandwidth. Alternatively, use virtual networks (VLANs) to segregate replication from production network traffic. Best Practices Planning 11

12 Sizing the DL3D 4000 In order to properly size the EDL and 3D4000, retention requirements must be thoroughly reviewed and changed to accommodate the changes introduced by de-duplication technology. Each system must be sized separately according to the retention scheme desired to take full advantage of the features of that system and may require backup policies to be re-evaluated. Storage capacity needs to be sized to adequately handle the amount of data anticipated to be retained in both native and de-duplicated format. Backups that are larger than expected or contain data that deduplicates poorly can require much more storage space. The EMC Disk Library and EMC DL3D Sizing Tools Practitioner s Guide provides more details on the information required to assess sizing requirements and the sizing tools available for this purpose. This guide is available to employees only on Powerlink. Best Practices Planning 12

13 Data de-duplication The 3D 4000 uses data de-duplication technology to cost-effectively retain months of backup data on disk. Data de-duplication reduces the amount of storage capacity required by eliminating redundant data and storing only unique data. The 3D 4000 will de-duplicate any data migrated to it from the EDL, regardless of the source backup application. The de-duplication ratio achieved, however, may vary depending on the data set. The following sections on data de-duplication provide more information on the factors affecting de-duplication. The process Backup data is written to virtual tapes in the EDL in their native format. As the EDL migrates the backup data to the 3D 4000, the 3D 4000 begins writing it to disk as is and initiates de-duplication on it as soon as it ingests 256 MB. The 3D 4000 continues actively de-duplicating the data stream during ingest, finishing when the migration completes. Note: The 3D 4000 accommodates data streams that are less than 256 MB in size and ensures that all data migrated to it is de-duplicated. The de-duplication process divides the native data into variable length blocks and calculates a signature for each block. For each signature, the de-duplication process determines if any other identical signature already exists, and if not, hardware-compresses the unique block and writes it to its data pool. If it finds any matches to these signatures, it replaces that redundant block with a pointer to the unique block so that only one copy of that data block will exist on disk. The metadata description (signatures and pointers) of the data is stored separately from the backup data on a RAID 6 LUN on the disk array in the 3D A metadata description is stored for all data de-duplicated within the 3D As additional data is migrated to the 3D 4000, its data is also broken down into variable length blocks whose signatures are compared against those for existing unique blocks. Only new unique blocks are stored along with pointers to existing unique blocks in the appropriate sequence that can be used to reconstitute the data. Key factors affecting the de-duplication ratio The ratio of the amount of storage space required to store the total number of backup datasets in a conventional disk storage system to the storage capacity used in a de-duplication system is referred to as the de-duplication ratio. There are many factors that affect de-duplication ratios. Some key factors include: Backup policies Whether performing backups of similar data according to a daily full or weekly full/incremental model, the amount of data storage required is essentially the same as only unique data is stored using either model. The de-duplication ratio would differ considerably as the storage capacity required over the same time for nonde-duplicated data by daily fulls is much greater than the weekly full/incremental model. Retaining data for longer periods of time improves the chance that common data will already exist in storage, and storage savings and improved storage performance can be realized. Change rate When the first data stream is de-duplicated, the number of unique blocks within it can vary widely depending on both the data type and backup application. The de-duplication process may find little or no data redundancy to 50 percent or more data redundancy. When multiple backups of the same policy are migrated to the 3D 4000, however, storage savings often increase significantly with each new dataset as only those data blocks that are unique to each backup need to be written to disk. In conventional business operations, this unique data may represent only 1-2 percent of the data present in each additional backup set. The remainder of the backup consists of pointers to data already present on the 3D Best Practices Planning 13

14 Data types Backups of user data such as text documents, PowerPoint presentations, spreadsheets, some database types, source code, and Exchange are known to contain redundant data and are good de-duplication candidates. Other data sources such as audio, video, and scanned images consist of unique data and are not good deduplication candidates unless backed up multiple times. Backup application For data management purposes, each backup software application adds metadata to the data being backed up. When the data de-duplication process understands the layout of the metadata, it optimizes the deduplication process and achieves greater data de-duplication ratios. Even without backup application optimization, the 3D 4000 can still process data from a nonoptimized backup application but at a lower data de-duplication ratio. Compression To achieve optimal data de-duplication, data that changes frequently should not be compressed at the client prior to backing up to the EDL to increase the matches the de-duplication engine can find in the data stream when it is migrated to the 3D Compressing frequently changing data at the client will most likely result in negligible redundancy and poor de-duplication ratios. Data that is compressed at the EDL will not affect de-duplication of that data. EDL-compressed data migrates uncompressed to the 3D 4000, thus ensuring the de-duplication can find the optimal number of matches in the data stream. The 3D 4000 will hardware-compress data it receives to maximize its storage capability. On the other hand, static data that is compressed and backed up multiple times will achieve improved deduplication ratios as the de-duplication process will find repeated matches between datasets. Encryption The data protection introduced by encryption makes it difficult for the de-duplication process to find redundant data blocks and achieve storage savings. If encryption is required, EMC recommends that you create either non-capacity optimized VTLs or virtual tape cartridges with de-duplication disabled for those backups. Alternatively, save the backup data in an unencrypted format (which would de-duplicate well), and then apply encryption to the data when it is written to physical tape for offsite, long-term storage. If your policy backs up multiple copies of the same encrypted data to disk, however, the de-duplication process will find repeated matches resulting in storage savings. Multiplexing Multiplexing adds additional header information to the data, lowering the de-duplication ratio. The 3D 4000 can de-duplicate an intermingled backup stream, but not at optimal rates. EMC recommends disabling multiplexing to optimize de-duplication results. Best Practices Planning 14

15 Configuring and using the DL3D 4000 EDLs with a back-end 3D 4000 present options for creating 3D-enabled or 3DR-enabled virtual tape libraries and tape cartridges specific for data that will be de-duplicated for long-term retention as well as new policies for governing data movement (migration) to the 3D 4000 and storage space reclamation on the EDL. This section focuses on options and policies associated with de-duplication that are managed through the EDL console. For more detailed procedures, refer to the EMC 3D 4000 Version 1.0 Quick Start Guide on Powerlink. Data de-duplication with replication (3DR capability) is an option for the DL3D DR-enabled libraries and tapes are used when the 3D with replication is licensed. Refer to Replication on page 21 for more information on this option. 3D/3DR-enabled libraries and tapes 3D-enabled virtual tape libraries can migrate data to the 3D 4000 for de-duplication. 3DR-enabled virtual tape libraries can migrate data to the 3D 4000 for de-duplication and replication to a target DL3D 4000 system. 3D and 3DR-enabled virtual tape libraries are created using the EDL s library creation wizard (Figure 5). Figure 5. 3D/3DR-enable option for virtual tape libraries All tapes created for a 3D/3DR-enabled library will be 3D/3DR-enabled by default. When creating tapes, however, the 3D/3DR-enabled option can be disabled (Figure 6) and a 3D/3DR-enabled library can contain tapes that are 3D/3DR-enabled, respectively, and tapes that are 3D/3DR-disabled. Data written to 3D/3DRdisabled tapes cannot migrate to the 3D Best Practices Planning 15

16 Figure 6. 3D/3DR-enable option for virtual tapes Existing tapes cannot become 3D/3DR-enabled and vice versa. Both 3D-enabled VTLs and 3D-enabled virtual tapes are identified by a D in the upper left of their respective icons. Both 3DR-enabled VTLs and 3DR-enabled virtual tapes are identified by a D in the upper left and an R in the upper right of their respective icons. Existing regular VTLs can be 3D/3DR-enabled (by right-clicking on the library and choosing the Capacity Optimized option) and 3D/3DR-enabled virtual tapes subsequently can be created for that VTL. A 3D/3DR-enabled library, however, cannot revert to a regular library once it is 3D/3DR-enabled. All tapes created for a regular virtual tape library (one that is not 3D/3DR-enabled) will be regular tapes. These VTLs cannot contain 3D/3DR-enabled tapes. Migration Data migration is the process of copying the data written to a 3D/3DR-enabled virtual tape on the EDL to the 3D D/3DR-enabled virtual tapes on the EDL containing unmigrated data have a yellow dot in the lower left of the virtual tape icon. Virtual tapes in VTLs that are not 3D/3DR-enabled or virtual tapes in 3D/3DR-enabled VTLs that are 3D/3DRdisabled are ignored by this migration process. Migration of data from the EDL to the 3D 4000 determines when the DL3D 4000 de-duplicates the data. Data migration can be performed manually but is initiated primarily through a trigger. This trigger can be time- or policy-based. The DL3D 4000 supports the following migration policies: Time-based data migration triggers: Daily - Data migration begins at the scheduled time each day. Weekly - Data migration begins on a certain day and time each week. Policy-based data migration triggers: And - Data migration begins only when all selected policy-based triggers are satisfied. Best Practices Planning 16

17 Or - Data migration begins when any selected policy-based triggers are satisfied. Age based - Data migration begins after the user-defined number of days have elapsed following the last backup. Disk capacity based - Data migration begins after reaching the user-defined disk space threshold. End of Backup - Data migration begins after a backup completes and the tape is unmounted from the drive. Only When Tape is Full - Data migration begins only if the tape is full and unmounted from the drive. Delay Migration After all policy-based triggers are satisfied, delays data migration until a user specified time The migration policy is selected when the 3D/3DR-enabled VTL is created using the EDL s library creation wizard (Figure 7). This policy can be changed at any time by right-clicking on the library in the Navigation tree and choosing the Capacity Optimized option. Figure 7. Migration policy selection All 3D/3DR-enabled virtual tapes in a given 3D/3DR-enabled VTL adhere to the triggers of that VTL. Changes to the data migration triggers of a VTL propagate down to all 3D/3DR-enabled tapes within it. 3D/3DR-enabled tapes located in the vault adhere to the triggers configured on their parent VTL (the last VTL the tapes were in prior to being moved to the vault). Reclamation Prior to data reclamation, the BSP reads/writes all data to/from the virtual tapes on the EDL. When the data migration of a 3D-enabled virtual tape to the 3D 4000 completes, a data reclamation process can be initiated to remove the data from the 3D/3DR-enabled virtual tape on the EDL, so that the data resides exclusively on the 3D 4000, thus freeing space on the EDL. When data reclamation occurs, the data present in the virtual tapes is removed from the EDL and replaced with a tape stub. This tape stub acts as a pointer to the corresponding migrated data residing in the 3D When the BSP accesses that tape, the EDL mounts the tape stub and the 3D 4000 mounts one of its drives for the VTL in which the data resides. The data will pass directly through the tape stub to/from the Best Practices Planning 17

18 3D A 3D/3DR-enabled virtual tape that is a tape stub has an s in the lower right of the virtual tape icon in the EDL. Although a BSP can write to tape stubs, EMC recommends not appending to stubbed tapes for the following reasons: A BSP writes to a tape until it reaches the end. The tape stub passes data directly to its tape equivalent in the 3D The maximum size of this tape equivalent is 2 TB and is not configurable. To ensure all data in the 3D 4000 tape equivalents can fit on the 3D 4000 as sized or a replicated tape can be exported to physical tape on a target EDL, EMC recommends not appending to stubbed tapes. The data represented by the tape stub resides in its entirety on the 3D Writing to tapes in the EDL that have been stubbed will incur a performance impact and can affect the SLA. All writes to the EDL tape stub must be redirected to the 3D 4000 and will be subject to inline de-duplication. Best practices: Backup and restore performance is much better for data in native format residing on the EDL when compared to its de-duplicated format on the 3D Therefore, keep data in native format as long as it is actively being used for backups (including appends), or is needed for quick restores. Perform reclamation only on full tapes in the EDL. Reclamation triggers: Reclamation on the EDL can be performed manually but is initiated primarily through a trigger. This trigger, set at the VTL level, defines when reclamation occurs. The reclamation triggers are: Immediate - Reclamation begins immediately after a successful migration. Used Space Threshold - Reclamation begins when a user-defined disk space threshold is reached. Retention Period - Reclamation begins after the user-defined number of days following a migration. Never - Reclamation never occurs. The reclamation trigger is selected when the 3D/3DR-enabled VTL is created using the EDL s library creation wizard (Figure 8). This trigger can be changed at any time by right-clicking on the library in the Navigation tree and choosing the Capacity Optimized option. All 3D/3DR-enabled virtual tapes in a given 3D/3DR-enabled VTL adhere to the triggers of that VTL. Changes to the reclamation trigger of a VTL propagate down to all 3D/3DR-enabled tapes within it. 3D/3DR-enabled tapes located in the vault adhere to the triggers configured on their parent VTL (the last VTL the tapes were in prior to being moved to the vault). Best Practices Planning 18

19 Figure 8 Reclamation trigger selection Re-using tapes that have been stubbed: When you expire and relabel a tape that has been stubbed on the DL3D 4000, the EDL replaces the tape stub with an empty 3D/3DR-enabled tape. All writes and reads will occur with the 3D/3DR-enabled tape on the EDL. The data previously written to the corresponding tape on the 3D 4000 will remain there until new data from the relabeled tape is migrated to it. Then the previous 3D 4000 tape data can go through the 3D 4000 space reclamation process. (See the section 3D 4000 space reclamation on page 31.) EDL features impacted by 3D The DL3D 4000 supports all features available with a standard DL4000 series model; however, some features are impacted when using 3D/3DR-enabled VTLs and tapes. Copying to or from physical tape through the EDL s import/export feature The DL3D 4000 does not support copying 3D/3DR-enabled virtual tapes to or from back-end physical tapes using the EDL s import/export functionality. The DL3D 4000 does support connecting a physical tape library to the EDL and importing or exporting non-3d/3dr-enabled tapes in native tape format for offsite storage. Likewise, the EDL s auto archive and tape caching features, which are set at the VTL level and automatically export virtual tapes off to corresponding physical tapes, cannot be enabled on 3D/3DRenabled VTLs. Non-3D/3DR-enabled VTLs can be configured with auto-archive or tape caching enabled. Refer to EDL flex ports on page 10 for information on connecting physical tape libraries to a DL3D Remote copy There are three types of remote copy: auto, policy-based, and manual. A 3D/3DR-enabled VTL cannot have auto remote copy enabled, but non-3d/3dr-enabled virtual tapes within that VTL can be remote copied manually or can be configured with a remote copy policy. When using the EDL s remote copy feature, keep in mind the following: Auto remote copy is not configurable on 3D/3DR-enabled VTLs or on any tapes within those VTLs. Best Practices Planning 19

20 Policy-based remote copy is configurable on non-3d/3dr-enabled tapes within 3D/3DR-enabled VTLs. Manual remote copy can be performed on non-3d/3dr-enabled tapes within 3D/3DR-enabled VTLs. Using consolidated media management 3D/3DR-enabled virtual libraries can be assigned to and used by the EDL s consolidated media management software just like any other virtual library. The consolidated media management cloning/duplication features give DL3D 4000 users the ability to copy data from a 3D/3DR-enabled virtual tapes to physical tape. It is important to note the DL3D 4000 software and the consolidated media management software both run off of the same Linux OS, and therefore all back-end physical devices, including those presented by the 3D 4000, will be visible to the consolidated media management software. Extreme care needs to be taken not to use the 3D 4000 devices when configuring the consolidated media management software. Tape shredding Attempting to shred a 3D/3DR-enabled tape is not recommended as some of the contents of that tape may exist in de-duplicated form on the 3D 4000 and it will not be possible to remove all data pointed to by that tape and could impact other tapes that reference the unique blocks associated with the tape to be shredded. Only non-3d/3dr-enabled tapes are eligible for tape shredding. Active engine failover (AEF) For DL3D 4000 systems configured for active engine failover (AEF), if an engine fails over while a migration of data to the 3D 4000 is in progress, that migration will fail. Likewise if a failback occurs while a migration is in progress on the engine being failed back to, the migration will also fail. But, once a system has successfully failed over, if a migration is triggered for tapes associated with VTLs on the failed engine, the migration will execute properly. When a migration fails, the EDL provides an alert both in attention required and in the event log. There is no option to retry failed migrations automatically, but depending on the migration trigger and the reason for the failure it may be automatically retried. For example if a time-based migration trigger policy specifies to migrate every day at 8 A.M., if the policy kicks off the migration and it subsequently fails before completing, the migration should try to kick off again at 8 A.M. the next day assuming the failover has occurred successfully. With policy-based migration, such as End of Backup, the migration will not restart until the tape is mounted and unmounted or until a user makes some change to the migration trigger to initiate migration. You can manually initiate migration to the 3D 4000 by right-clicking on the tape that failed to migrate and selecting migrate to 3D. This will restart the migration from the very beginning of the tape, not from the point where the migration failed. Upgrading For EMC Disk Libraries, 4000 series models must upgrade to version 3.2 SP1 (minimum). The DL3D 3000 cannot be upgraded to 3D Best Practices Planning 20

21 Replication Replication is an optional licensed feature for the DL3D 4000 and is supported in the following configuration: DL3D 4000 to DL3D 4000 (1:1 only) Replication is accomplished by exchanging unique blocks between source and target 3D 4000s and only sending new data blocks not present at the disaster recovery site. Figure 9 is a high-level depiction of the replication environment. Figure 9. DL3D 4000 replication Replication transmits data over Ethernet using TCP. The source 3D 4000 can optionally encrypt the data inline using AES-128 before sending it across the TCP link to the target 3D 4000 where it is unencrypted before it is stored. The 3D 4000 uses TCP port 1062 for replication. Refer to the section 3D 4000 Ethernet connectivity on page 11 for more information. Overview In a replication environment, there are two DL3D 4000 systems: a source and a target. For replication, the BSP writes backup data to 3DR-enabled tapes in 3DR-enabled libraries in the source DL3D The source EDL migrates the data in the 3DR-enabled tapes to its 3D 4000 where it is de-duplicated and continuously replicated to the target 3D 4000 over a WAN. This continuous replication occurs until the deduplicated data pool in the source 3D 4000 matches the data pool in the target 3D Only the data migrated to the source 3D 4000 from 3DR-enabled tapes is replicated. Data migrated from 3D-enabled tapes to the source 3D 4000 is not eligible for replication. Replication is a three-step process: 1. All unique blocks associated with the 3DR-enabled tapes copy from the source 3D 4000 to the target 3D This process of replicating unique blocks begins as soon as the data de-duplicates and occurs Best Practices Planning 21

22 continuously until the block pools on the source and target 3D 4000s match. This is referred to as continuous replication. 2. A checkpoint replication operation is performed by the source 3D This checkpoint replication verifies whether all the blocks associated with the 3DR-enabled tapes are present on the target 3D 4000 and copies the description of the de-duplication backup images to the target 3D Once checkpoint replication occurs, the target 3D 4000 automatically populates the replicated tapes into EMC:DL4000 libraries present under the Physical Tape Libraries tab on the target EDL console. Checkpoint replication can be scheduled to occur once every 24-hour period or be done manually at any time. See Checkpointing on page 23 for more information. 3. The replicated tapes must be brought into a VTL on the target EDL so they can be accessed by a BSP connected to that EDL. The tapes can be brought into a VTL by creating a direct linked tape or by performing a copy mode import. Additional configuration requirements The 3D 4000 manages the storage space occupied by the unique data by removing unique blocks that have no references using a process called space reclamation (see 3D 4000 space reclamation on page 31). This space reclamation feature is set by default to run once weekly at noon on Sunday. It is important that this process not occur on the target 3D 4000 until a replication checkpoint has successfully completed on all replicated tapes. To ensure that this happens, EMC recommends disabling scheduled space reclamation on the target 3D 4000 at initial replication setup and performing it manually only after verifying that all replications are successful and complete. If replication is bi-directional, disable scheduled space replication on both the source and target 3D Initial setup Prior to the first replication, it is important to replicate the checkpoint (using Replicate Now ) for the virtual tape libraries on the source 3D 4000 before writing any data to the 3DR-enabled tapes. This action establishes the structure for the replication image on the target 3D 4000 and expedites the first replication that occurs after the first backup. Replicating the empty checkpoint structure has shown that the speed of the first replication will be up to twice as fast than performing the first checkpointing operation after one or more migrations have occurred to 3DR-enabled tapes. Initial replication (first data copy) is a timeconsuming operation and will usually take significantly more time than later replications because the data is typically new and unknown to the target 3D For first-time replication, it may be desirable to co-locate the source and target DL3D 4000s so that they are on a dedicated Ethernet network and replicate locally. This will facilitate the transfer of the large amount of data produced by the first migration to the source 3D 4000 to the target 3D For first-time replication, the goal is to seed the target 3D 4000 with the same data in the 3DR-enabled tapes on the source 3D 4000 so that the minimum amount of data needs to be transferred between units on subsequent replications to maintain synchronization. Performing a replication It is assumed that both the target and source systems are attached to your network, that they are configured as a replication pair, and that replication has been enabled on the source 3D 4000 system. In order to replicate from a source DL3D 4000 to a target DL3D 4000, the following setup is required: 1. Using the EDL console on the source DL3D 4000 system, create 3DR-enabled libraries and tapes on the source EDL and set the migration policy. Only data written to 3DR-enabled cartridges can be replicated. Refer to Configuring and using the DL3D 4000 on page 15 and the EMC 3D 4000 Version 1.0 Quick Start Guide on Powerlink for more information Best Practices Planning 22

23 2. Prior to migrating data to the source 3D 4000 for replication for the first time, perform a manual checkpoint replication. See On-demand replication checkpoint on page 27 for more information. This replication checkpoint establishes the structure for the replication image on the target 3D 4000 and expedites the first replication that occurs after the first backup to a 3DR-enabled VTL. Replicating the empty checkpoint structure when the 3DR-enabled VTL is initially created has shown that the speed of the first replication will be up to twice as fast than performing the first checkpointing operation after one or more backups have occurred to that VTL. Initial replication (first data copy) is a time-consuming operation and will usually take significantly more time than later replications because the data is typically new and unknown to the target 3D For first-time replication, it may be desirable to co-locate the source and target 3D 4000s to facilitate the transfer of the large amount of data produced by the first backup to the source library to the target DL3D Co-locate the source and target DL3D 4000 so that they are on a dedicated Ethernet network and replicate locally. This will allow the initial replication to proceed at the fastest possible Internet rate. When the initial replication completes, the target DL3D 4000 can be deployed to its intended location. 3. Schedule a checkpoint replication. See Scheduled replication checkpoint on page 29 for more information. Begin performing backups to the source 3DR-enabled VTL. As backups are migrated to the source 3D 4000, the de-duplication process places the unique blocks in a queue for replication as well as hardwarecompresses them and writes them to its storage. For each unique block in the queue, the source 3D 4000 queries the target 3D 4000 to determine if that block of data already is present on the target. If not, it replicates the unique block to the target. If it does, it goes to the next entry in the queue. This process occurs continuously between the systems. Checkpointing On-demand replication checkpointing and scheduled checkpointing are done through the 3D 4000 GUI of the source DL3D 4000 system. See Performing a replication checkpoint operation on page 27 for more information. Replication checkpointing copies the metadata description of the 3DR-enabled virtual tapes replicated to the target system. This checkpointing operation provides the information necessary to be able to recover the replicated data. Checkpointing can be scheduled to occur once per day or be performed on-demand. It should only take place after all data in the 3DR-enabled tapes is present on the target system. The scheduling of these activities will affect the availability of recoverable data on the target site. The 10 most recent checkpoint replications of each 3DR-enabled tape are maintained on the target 3D Before performing an on-demand checkpointing operation on the 3D 4000, it is recommended to perform a readiness check (a selection available when performing on-demand checkpointing). This will allow the source 3D 4000 to query the target 3D 4000 and verify that all data blocks associated with the 3DR-enabled tapes have been transferred and are present on the target 3D Once the Check Readiness operation is successful, a checkpoint operation performed on the partition will ensure that a full recovery all virtual tapes can occur. Checkpointing before all data is available results in a partial checkpoint as only the metadata associated with the data that has already been replicated is sent to the target 3D The 3D 4000 can also be scheduled to perform a replication checkpoint once every 24-hour period. If the 3D 4000 attempts a scheduled checkpoint operation and all the unique data associated with 3DR-enabled tapes is not yet at the target 3D 4000, a partial checkpoint occurs and only some of the tapes are available for recovery. Therefore scheduling checkpointing to occur after replication completes ensures that all replicated data is available. When performing a checkpoint operation, keep the following in mind: 3DR-enabled tapes should be unloaded from the tape drive so the tape is available for checkpointing. Checkpointing should be initiated after the 3DR-enabled tapes have finished de-duplicating and replicating to the target 3D Best Practices Planning 23

24 Since checkpointing can only be scheduled once per day, this may have an impact on your SLA if you backup more than once per day. If the 3DR-enabled tapes have not fully replicated before the checkpoint operation is scheduled to occur, a partial checkpoint will result and not all of the 3DR-enabled tapes will be available at the target 3D Target side recovery Should a VTL become unavailable on a source DL3D 4000, two methods are available to access the data at the target system: direct linked tapes or copy import. These two methods are options available through the target DL3D 4000 s EDL console. Detecting replicated tapes on the target DL3D 4000 The first step in accessing replicated 3DR-enabled tapes is to detect the replicated tapes on the target EDL. When 3DR-enabled tapes replicate from the source 3D 4000 to the target 3D 4000, the replicated tapes are automatically populated across the target 3D 4000 libraries. The target libraries, which appear as EMC:DL4000 libraries under the Physical Tape Libraries section of the target EDL console, need to be inventoried to detect the 3DR-enabled tapes present on the target 3D To do this, right-click on each of the EMC:DL4000 libraries and select Inventory (Figure 10). Figure 10. Inventorying the target 3D 4000 libraries for replicated tapes When the inventory completes, the replicated tapes will appear under the Physical Tapes tab in the righthand pane (Figure 11). Figure 11. Replicated tapes Best Practices Planning 24

25 Once the replicated tapes have been detected they can be accessed by creating direct-linked tapes or by importing the tapes on the target EDL. Direct-linked tapes Creating direct-linked tapes generates tape stubs on the EDL VTL that are linked to the replicated data on the 3D When a BSP uses the tape (stub) on the VTL, the data passes through the EDL directly from the replicated data on the target 3D Note: Tape stubs linked to replicated data on the 3D 4000 are read-only. Advantages of direct-linked tapes are: It is the fastest way to bring 3D 4000 replicated tapes into an EDL VTL for use by a BSP. The de-duplicated data resides on the 3D 4000, taking up the smallest amount of physical storage. Follow these steps to create direct-linked tapes: 1. Inventory the EMC:DL4000 libraries on the target EDL as described in Detecting replicated tapes on the target DL3D Create a VTL (or choose an existing VTL) on the EDL. 3. Enable 3D with Replication on the selected VTL. 4. Right-click on the VTL and select Sync Library. A list of all 3DR resources and physical libraries appears. 5. Select the library containing the replicated tapes and click Next. A list of replicated tapes residing in the library appears. 6. Select the tapes you want to bring into the VTL and click Next. The various modes for synchronizing with the physical library displays. 7. Select Create Direct Link and click Next. 8. Click Finish to confirm. Copy mode imports Copy mode imports copies the replicated data on the target 3D 4000 onto virtual tape in a VTL on the target EDL. Advantages of copy mode imports are: Once the tapes are copied onto the target EDL, the restore performance will be that of the EDL and no longer limited by the restore performance of the 3D Replicated tapes copied into the EDL can be exported to physical tape. Follow these steps to copy the replicated tapes into a VTL on the EDL: 1. Inventory the EMC:DL4000 libraries on the target EDL as described in Detecting replicated tapes on the target DL3D Create a VTL (or choose an existing VTL) on the EDL for the replicated tapes. Best Practices Planning 25

26 3. Right-click the library (EMC:DL4000) containing the replicated tapes, and select Import Tape. A list of all VTLs defined in the EDL appears. 4. Select the VTL to import the replicated tapes, and click Next. The various modes for importing the tapes into the EDL appear. 5. Select Copy Mode and click Next. The list of replicated tapes residing in the library appears. 6. Select the tapes to bring into the VTL and click Next. 7. Click Finish to confirm. It is strongly recommended that the VTL configured on the target EDL for the replicated tapes is of the same library type and drive type as the VTL on the host EDL used to create the original tapes. Performance impacts Network latency will have a significant impact on replication performance. Consult with your local EMC performance specialist to ensure optimum network configuration. 128-bit AES encryption for replication is available. Encryption may affect replication performance. It should be disabled if the customer s WAN is already secured. Best Practices Planning 26

27 Configuring 3D 4000-specific operations In general, almost all data management activities with the 3D 4000 are managed through the console of the EDL to which it is attached. There are only a few operations that may need to be performed through the 3D 4000 GUI. Refer to the EMC 3D 4000 Version 1.0 Quick Start Guide on Powerlink for more detailed steps on performing these operations. Performing a replication checkpoint operation The replication checkpoint operation can be done on-demand, or scheduled to occur once daily. The target 3D 4000 will retain the latest 10 copies of each replicated tape that was checkpointed from the source 3D It is important that this replication checkpoint operation align correctly with off-site data backup and recovery schedules. Perform it after replication of the de-duplicated data completes in order to ensure all data is recoverable. The procedures for both performing an on-demand replication checkpoint as well as scheduling a replication checkpoint for a particular time of day are outlined here. On-demand replication checkpoint Before performing an on-demand replication checkpoint operation on the 3D 4000, EMC recommends executing a readiness check (in Figure 12, it is the Check Readiness button). This readiness check causes the source 3D 4000 to query the target 3D 4000 and verify that all data blocks have been transferred to and are present on the target 3D If the Check Readiness operation returns success, proceed with the replication checkpoint (in Figure 12, the Replicate Now button). If a different status is returned, it is likely that there is still data being deduplicated or transferred to the target 3D Retry the check readiness process at a later time. Although an on-demand replication checkpoint operation can be performed, it will result in a partial checkpoint. That is, only the data on the source 3D 4000 that had already been replicated is available at the target. An on-demand replication checkpoint operation, unlike a scheduled replication checkpoint, can be performed several times a day. This can be important if more than one backup occurs per day or a backup window was missed that can result in a partial checkpoint. Best Practices Planning 27

28 Figure 12. Selecting a VTL to "Check Readiness" When a replication checkpoint operation begins, the VTL replication status screen indicates that the VTL replication checkpoint operation is in process (Queued). When the replication checkpoint operation completes, the status changes to successful on the source 3D 4000 (Figure 12) and target 3D 4000 (Figure 13). Best Practices Planning 28

29 Figure 13. Checkpoint replication complete status The replicated tapes are now available on the target 3D 4000 for recovery and failback operations. Scheduled replication checkpoint The replication checkpoint operation can be scheduled once per day (Figure 14). If all data associated with the replicated tapes is not present on the target system at the time the replication checkpoint executes, the source 3D 4000 will perform a partial checkpoint. That is, only the data on the source 3D 4000 that had already been replicated to the target 3D 4000 is available in that recovery point. Best Practices Planning 29

30 Figure 14. Setting a time for a scheduled checkpoint replication Failback of replicated tapes In a disaster recovery scenario in which the source DL3D 4000 is lost, 3DR-enabled tapes that have been replicated to the target 3D 4000 can be replicated back to the source DL3D 4000 as soon as the source DL3D 4000 is rebuilt. Since failback of replicated tapes is designed for disaster recovery purposes only, failback is intended solely for the use of EMC support. To fail back replicated tapes, perform the following steps: 1. On the target 3D 4000 GUI, click Replication > Target Role > VTL (Figure 15). Best Practices Planning 30

31 Figure 15. Libraries containing replicated tapes on the target 3D For each of the eight libraries, select the latest replicated image and click Failback. Clicking Failback initiates replication of the 3DR-enable tapes back to the source DL3D Shortly after replication of the 3DR-enabled tapes back to the source 3D 4000 completes, the tapes automatically populate across the target libraries on the source 3D The data can then be brought into the source EDL following the same steps described in Target side recovery on page 24. 3D 4000 space reclamation This section describes how space occupied by unique blocks that are no longer referenced are reclaimed on the 3D It is a separate operation from the reclamation process on the EDL. When a backup stream is ingested, the native format data is written to a tape cartridge in the EDL. If it is written to 3D/3DR-enabled virtual tapes, the data later migrates to the 3D 4000 for de-duplication. The data now exists on the EDL in native format and the 3D 4000 in de-duplicated format. When a tape is no longer actively being used for backups (including appends), or is needed for quick restores, the reclamation process (see Reclamation on page 17) can free storage capacity on the EDL while permitting long-term onsite retention of the data on the 3D When a tape s retention expires, the space occupied by the tape stub (or native format data if reclamation was not performed) on the EDL and the de-duplicated data associated with the tape on the 3D 4000 can be recovered with the BSP. When a BSP expires a tape, there is no direct communication of the event to the EDL. As a result, the DL3D 4000 will still indicate that tape contains data and therefore still occupies storage space. For the DL3D 4000 to re-use the tape, the BSP must also relabel the volume by writing a data block to the beginning of the scratch volume. Expiring and relabeling EDL 3D/3DR-enabled tapes will allow the DL3D Best Practices Planning 31

32 4000 to remove the tape stub and recover the de-duplicated data space associated with those tapes when the new data written to the relabeled tape is migrated to the 3D Best practices: Configure the BSP to use expired tapes before scratch tapes as expired tapes still consume space on the DL3D 4000 until space reclamation has been run. 3D 4000 space reclamation cannot occur on data associated with expired and relabeled media until new data written to the relabeled tape is migrated to the 3D The 3D 4000 space reclamation process to dereference and subsequently delete the unique blocks associated with the backups on the previous contents of the tape can then occur. Either create a backup script or properly size the number of tapes required so tapes are relabeled as they are reused. Backup software will always use the least recently used tape and if there are a lot of unnecessary tapes, reclamation will be inefficient. The 3D 4000 space reclamation process deletes the metadata indices associated with that tape as well as any pointers to unique blocks present in other de-duplicated backups. Then it recovers the storage space consumed by the unique blocks associated with that tape that are no longer referenced. If the BSP is not configured to overwrite the volume label when it moves it to scratch, the de-duplicated data associated with that tape remains on the 3D 4000 and the 3D 4000 s space reclamation feature will not recover any storage space. The space reclamation process can be scheduled or run manually using the Space Management function available through the 3D 4000 GUI. By default, it is set to run once weekly at noon on Sunday. There is significant overhead associated with this process and it should not be run during periods of high appliance use. Replication, reclamation, and data stream ingest all consume system resources and therefore should not all be done at the same time without understanding overall system performance implications. Figure 16. Scheduling 3D 4000 space reclamation Space reclamation will also be activated automatically in the event 3D 4000 storage capacity reaches 95 percent full. Best Practices Planning 32