Applied Technology Abstract This white paper examines deployment and integration of DB2 on z/os on EMC Symmetrix VMAX arrays. Details of integration with new features provided by Symmetrix VMAX arrays are documented with practical examples for storage and database administrators. May 2010
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Table of Contents Executive summary...4 Introduction...4 Audience... 4 Technology overview...5 Storage device support... 5 Enterprise Flash drives... 5 Virtual LUN (VLUN) migration feature... 6 FICON... 7 TimeFinder improvements... 7 Large volume support... 7 Large volume benefits... 7 TimeFinder/Clone cascading clones... 8 TimeFinder/Snap Recreate... 8 SRDF/Extended Distance Protection... 9 SRDF Enginuity Consistency Assist... 10 SRDF/A adding or removing devices... 10 Remote TimeFinder/Clone restore to SRDF R1... 10 SRDF/Star with an R22 device... 10 Additional capabilities...10 Conclusion...11 Applied Technology 3
Executive summary The EMC Symmetrix VMAX Series with Enginuity is a new entry in the Symmetrix family. Built on the strategy of simple, intelligent, modular storage, it incorporates a new scalable fabric interconnect design that allows the storage array to seamlessly grow from an entry-level configuration into the world s largest storage system. The Symmetrix VMAX provides improved performance and scalability for demanding enterprise storage environments while maintaining support for EMC s broad portfolio of platform software offerings. The Enginuity operating environment for Symmetrix version 5874 is a new, feature-rich Enginuity release supporting the Symmetrix VMAX storage arrays. With the release of Enginuity 5874, Symmetrix VMAX systems deliver new software capabilities that improve capacity utilization, ease of use, business continuity, and security. The Enginuity operating environment provides the intelligence that controls all components in an EMC Symmetrix storage array. It is an intelligent, multi-tasking, preemptive storage operating environment that controls storage data flow. It is completely devoted to storage operations and optimized for the service levels required in high-end enterprise environments. While it shares many characteristics with the operating systems typically used to run large host computers, Enginuity is more specialized and specifically optimized for storage-based functions. It is driven by real-time events related to the input and output of data. It applies self-optimizing intelligence to deliver the ultimate performance, availability, and data integrity required in a platform for advanced storage functionality. A prerequisite for complex, demanding, risk-intolerant IT infrastructures, Enginuity coupled with Symmetrix is the essential foundation technology for delivering advanced and cost-effective high-end storage services. Enginuity, as a proven storage operating environment, carries all of its extended and systematic development forward in each successive Symmetrix platform generation a major operational and investment protection benefit to users. This means that all of the reliability, availability, and serviceability features, all of the interoperability and host operating systems coverage, and all of the application software capabilities developed by EMC and its partners continue to perform productively and seamlessly even as underlying technology is completely refreshed. All of these features and capabilities are fully operational from day one in each Symmetrix platform, including the VMAX. The Symmetrix VMAX also maintains customer expectations for high-end storage in terms of availability. High-end availability is more than just redundancy; it means nondisruptive operations and upgrades, and being always online. Symmetrix VMAX provides: Nondisruptive expansion of capacity and performance at a lower price point Sophisticated migration for multiple storage tiers within the array The power to maintain service levels and functionality as consolidation grows Simplified control for provisioning in complex environments Introduction Many of the new features provided by the new EMC Symmetrix VMAX platform can reduce operational costs for customers deploying DB2 z/os solutions, as well as enhance functionality to enable greater benefits. This white paper details those features that provide significant benefits to customers utilizing DB2 on z/os. Audience This white paper is intended for DB2 z/os database administrators, z/os storage administrators and architects, customers, and EMC field personnel who want to understand the implementation of new features and functions that can provide additional benefits in an EMC Symmetrix VMAX environment. Applied Technology 4
Technology overview Storage device support The new VMAX offers improved disk drive support in the areas of performance and capacity. The following is a list of the newer capabilities of the Symmetrix VMAX. Please note that VMAX now supports only 4 Gb drives on the back-end loop. Ultra-high performance: Flash (SSD) 200 GB 400 GB High performance: 4 Gb FC (15k) 146 GB 300 GB 450 GB Price / performance: 4 Gb FC (10k) 400 GB High capacity: SATA (7.2k) 3 Gb SATA - Adapted to 4 Gb FC using NorthStar 1 TB These disk drives form an extensive price performance offering that enables customers to get the most out of their DB2 on z/os deployments by choosing the disk storage tier most appropriate to the DB2 data that is resident on it. Enterprise Flash drives Like Symmetrix DMX-4, Symmetrix VMAX storage arrays support enterprise Flash drives (EFDs). Both Symmetrix DMX-4 and VMAX arrays support 200 GB and 400 GB Flash drives with a 4 Gb attachment. With Flash drives, EMC has created a new ultra-performance storage tier, Tier 0, that removes previous performance limitations imposed by magnetic disk drives. For years, the most demanding enterprise applications have been limited by the performance of magnetic disk media. Tier 1 performance in storage arrays has been constrained by the physical limitations of hard disk drives. Enterprise Flash drives for Tier 0 deliver unprecedented performance and response times, which are benefits well suited for demanding DB2 z/os configurations. Enterprise Flash drives dramatically increase performance for latency-sensitive databases like DB2 z/os. Enterprise Flash drives, also known as solid state drives (SSD), contain no moving parts, which removes much of the storage latency delay associated with traditional magnetic disk drives. A Symmetrix VMAX with enterprise Flash drives can deliver single-millisecond application response times and up to 30 times more I/O operations per second (IOPS) than traditional Fibre Channel hard disk drives (HDD). Additionally, because there are no mechanical components, Flash drives consume significantly less energy than hard disk drives. When replacing a larger number of HDDs with a lesser number of enterprise Flash drives, energy consumption can be reduced by up to 98 percent for a given IOPS workload. The high-performance characteristics of enterprise Flash drives eliminate the need for organizations to purchase large numbers of traditional hard disk drives, while only utilizing a small portion of their capacity to satisfy the IOPS requirements of DB2 for z/os subsystems. The practice of underutilizing a hard disk drive for increased performance is commonly referred to as short-stroking. Enterprise Flash drives can increase DB2 for z/os systems performance and eliminate the need to short-stroke drives, thus keeping storage footprint and power consumption to a minimum and reducing total cost of ownership (TCO). Applied Technology 5
Virtual LUN (VLUN) migration feature This new feature offers DB2 z/os DBAs the ability to transparently migrate DB2 volumes from differing tiers of storage as shown in the previous section as well as from differing tiers of protection. The DB2 volumes can be migrated to either unallocated space (also referred to as unconfigured space) or to configured space, which is defined as existing Symmetrix volumes that are not currently assigned to a server - existing, not-ready volumes - within the same subsystem. The data on the original source volumes is cleared using instant VTOC once the migration has been deemed successful. The migration does not require swap or DVR space, and is nondisruptive to the attached DB2 systems and other internal Symmetrix applications such as TimeFinder and SRDF. The valid migration combinations of drive types and protection types for the migration are summarized in the following tables. Figure 1. Virtual LUN Eligibility Tables The device migration is completely transparent to z/os since the operation is executed against the Symmetrix device; thus the UCB address is not changed and DB2 operations are uninterrupted. Furthermore, in SRDF environments, the migration does not require customers to re-establish their disaster recovery protection after the migration. This Virtual LUN feature leverages the newly composed virtual RAID architecture in Enginuity 5874 that abstracts the device protection from its logical representation to a z/os host. This powerful approach allows a device to have more simultaneous protection types such as BCVs, SRDF, concurrent SRDF, and spares. It also enables seamless transition from one protection type to another while hosts and their associated applications, and Symmetrix software are accessing the device. This Virtual LUN feature offers the z/os community a long awaited capability to utilize SATA storage a much cheaper, yet reliable, form of capacity storage. It also facilitates fluid movement of data across the various storage tiers present within the subsystem. the realization of true tiered storage in the box. Thus, Symmetrix VMAX becomes the first enterprise storage subsystem to offer a comprehensive tiered storage in the box, ILM capability that complements the customer s SMS and HSM initiatives completely. Customers can now achieve varied cost/performance initiatives by moving lower priority application data to less expensive storage, or conversely, moving higher priority or critical application data to higher performing storage as their needs dictate. Applied Technology 6
FICON Enginuity 5874 and Symmetrix VMAX introduce two-port support for the FICON instances and provide support for a total of 64 FICON channels. This is the first multi-port solution for FICON to be offered. Each FICON instance pair can support either one or two ports with both physical ports managed by the LINK instance (EE slice); for any FICON instance pair, either or both of the ports may be physically cabled. Since Symmetrix VMAX can only be configured as control unit type 2107, all of the channel commands defined in the 2107 command and feature set are supported. Also, FICON supports a set of commands based on the 3370 command set, which allows access to Fixed Block Architecture (FBA) devices. Support is provided for all of the standard 3380 and 3390 devices sizes, in addition to the various custom sizes. TimeFinder improvements The classic underlying Enginuity mechanism responsible for creating mirrored local replicas will no longer be supported with Enginuity 5874 microcode. However, the classic TimeFinder/Mirror user command sets will continue to be supported by TimeFinder/Clone using the TimeFinder/Mirror emulation capabilities. Thus, starting with Enginuity 5874, there is a single technology in use, which is clone emulation. Furthermore, whenever TimeFinder/Mirror detects a Symmetrix controller running at Enginuity level 5874 and later, it will automatically set the mode to clone emulation. Customers using DB2 and TimeFinder/Mirror will not experience any changes other than the increased capability to make more copies of their DB2 subsystems than before. Large volume support Enginuity 5874 introduces the ability to create and utilize logical volumes that can be up to 262,668 cylinders in size. These large volumes are supported as an IBM 3390 format with a capacity of up to 223 GB and are configured as 3390 Model As. This large volume size matches the capacity announced in z/os 1.10 for 3390 Extended Address Volumes (EAV); IBM defines an EAV to be any volume that is greater than 65,520 cylinders, hence any subset volume size greater than 65,520 cylinders and less than or equal to 262,668 cylinders is, in fact, an EAV. An EAV, though currently limited to 262,668 cylinders, has a defined architectural limit of 268,434,453 cylinders. With Enginuity 5874, large volumes may be configured and used in a similar manner to the old, regular devices that users are already familiar with. While large volumes can co-exist alongside the older volumes there are limitations to their use imposed by certain access methods (operating system restrictions), and other independent vendors software. The collected reference to the space above 65,520 cylinders is known as the extended addressing space (EAS), while the space below 65,520 cylinders is referred to as the base addressing space. Today, the major exploiter of the EAS portions of EAVs are applications using any form of VSAM (KSDS, RRDS, ESDS and linear); this covers DB2, IMS, CICS, zfs, and NFS. A few restrictions are notable with z/os 1.10 with respect to VSAM data sets not supported in the EAS; they are catalogs, paging spaces, VVDS datasets, and those with KEYRANGE or IMBED attributes. Large volume benefits Large volumes offer the ability to consolidate many smaller volumes onto a single device address. This, in turn, goes a long way in solving the sprawling device configurations that placed users at the Logical Partition (LPAR) device limit of 65,280 devices. In fact, the two main culprits of device sprawl in many environments are the excessive and prolonged use of very small volume sizes (3390-3, 3390-9, etc.), and the significant and growing business continuity requirements as business applications proliferate. Not only are large volumes an important component in the device consolidation strategy, but it is quickly recognized as an even more vital component in providing the very high z/os subsystem capacities required Applied Technology 7
by the newer class of applications running on the ever more powerful processors. In short, even with a few addresses configured with these large capacities, the result is very large subsystem capacities. One of the stated goals of large volumes and the accompanying reduction of device addresses required to support them is the overall simplification of the storage subsystem and hence, the reduction of storage management costs. This has a direct impact on storage personnel productivity, and proves to be a strong determinant in its adoption. Last, but certainly not least, is the reduction of processor resources associated with multi-volume usage and processing since datasets and clusters can now be wholly contained within large enough single extents, thereby relegating multi-volume extents and their drawbacks to something of user preference and choice rather than necessity. The reduction in frequency of OPEN/CLOSE/End of Volume processing will help expedite many currently long running batch jobs. TimeFinder/Clone cascading clones DB2 customers often have expressed the desire to be able to create multiple replicas of a given DB2 system. They may want to be able to create a backup image of the given DB and retain that image, but then also be able to repurpose that image for a reporting system, for example. Typically those replicas are required to be fully independent the backup image should not be a TimeFinder/Snap off the production instance as that can direct workload back to the production volumes. Equally keeping the copy to be used for reporting independent of the backup image is required to isolate workloads (for example, if the reporting instance is in operation when the next backup cycle occurs, this would generate a significant workload, and impact the resync of the backup clone). TimeFinder/Clone version 7.0 with Enginuity 5874 supports cascading clones. Cascading clones is the ability for a clone operation to take place with a device that is already involved in a clone operation. For example, you can clone Device A to Device B and then Device B to Device C. Figure 2 depicts the relationships: A B C clone clone DB2 Database Figure 2. Cascading clone The DB2 z/os database on the A volumes is cloned to the B volumes. After the copy has completed, the B volumes can be cloned to the C volumes. The key issue here is that the incremental relationship between A and B remains intact and subsequent clones from A to B are incremental within the storage controller. TimeFinder/Snap Recreate Customers using TimeFinder/Snap with DB2 have asked for a more efficient way to recreate existing Snap sessions. Presently they have to terminate the snap, perform a create, and then an activate. If none of the volume relationships had changed this seemed to be a lot of unnecessary work. In the 5874 microcode there is a new Snap recreate function that replaces the terminate and create function. There is a lot less data to manipulate and consequently the operation is also much faster. Applied Technology 8
SRDF/Extended Distance Protection Enginuity 5874 supports a new feature called SRDF/Extended Distance Protection (SRDF/EDP). This feature allows a much more optimized and efficient structure to a three-site SRDF topology in that it allows the intermediate site Site B, in an A to B to C topology to have a new device type known as a diskless R21 (Figure 3). This arrangement requires that the Secondary (Site B) subsystem to be at Enginuity 5874 or later (and Symmetrix VMAX), while Sites A and C could be running either DMX-4 with Enginuity 5873 or Symmetrix VMAX with Enginuity 5874 or later. Thus, SRDF/EDP allows replication between the primary Site A and tertiary Site B without the need for RDF BCVs or any replication at the secondary site B. Figure 3 depicts a simple SRDF/EDP configuration. Primary Site A Enginuity 5773 or Secondary Site B Enginuity 5874 Tertiary Site C Enginuity 5773 or 5874 5874 Figure 3. SRDF/EDP configuration This diskless R21 differs from the real disk R21, introduced in an earlier release of Enginuity, which had three mirrors one at each of the three sites. The diskless R21 device is a new type of device that does not have any local mirrors. Further, it has no local disk space allocated on which to store the user data, hence it reduces the cost of having disk storage in the Site B subsystem. This results in only two full copies of data, one on the source Site A and one on the target Site C. The purpose of a diskless R21 device is to cascade data directly to the remote R2 disk device. When using a diskless R21 device, the changed tracks received from the R1 mirror are saved in cache until these tracks are sent to the R2 disk device. Once the data is sent to the R2 device and the receipt is acknowledged, the cache slot is freed and the data no longer exists on the R21 Symmetrix. This meritorious approach to three-site SRDF means that a customer will only need a Symmetrix system with vault and SFS drives plus enough cache to hold common area, user data/updates (customer data), and device tables, thereby reducing the overall solution cost. It highlights a serious attempt to address a greener alternative to the device sprawl brought about by multi-site business continuity requirements and is sure to be welcomed by many customers deploying three-site DR solutions. The R21 diskless device still uses the device table like a disk device and will also consume a symm number. Further, they are not addressable by a host or assigned to a DA and hence cannot be accessed for any I/Os. Other restrictions on diskless R21 devices include the following: They can only be supported on GigE and Fibre Channel directors. They cannot participate in dynamic sparing since the DA microcode blocks any type of sparing and doing ivtoc against them. They cannot be RDF paired with other diskless devices. When used for SRDF/A operations, all devices in the SRDF/A session must be diskless; non-diskless device types are not allowed. All Symmetrix replication technologies other than RDF (TimeFinder, Snap, and Clone) will not function with diskless devices configured as either the source or the target of the intended operation. However, SDDF sessions are allowed on diskless devices. Applied Technology 9
SRDF Enginuity Consistency Assist SRDF-ECA provides consistency protection for synchronous mode volumes by performing suspend operations across all SRDF/S volumes in a consistency group or a named subset of all volumes in a composite group. In Enginuity 5773 and earlier versions, in a concurrent SRDF environment, SRDF-ECA could only be enabled on a single link or on both links of the concurrent SRDF relationship at the same time. Enginuity 5874 allows for the definition of an independent SRDF-ECA consistency group on each of the links of a concurrent SRDF R1 volume, providing the ability to disable consistency protection on one link while still maintaining consistency on the second leg. SRDF/A adding or removing devices The functionality of adding and removing devices to an existing SRDF/A SRDF group has been greatly enhanced in Enginuity 5874. The functionality, called the consistency exempt feature, provides the ability to dynamically add and remove volumes from an active SRDF/A session. Furthermore, it does this without affecting the state of the session or the reporting of the SRDF pair state for each of the volumes in the active session that are not the target of the operation. This is achieved by marking the volumes being added or removed as exempt from being considered when calculating the consistency state of the volumes in the SRDF/A session, or when deciding if the SRDF/A session should be dropped to maintain dependent write consistency on the R2 side. Setting the consistency exempt flag on a volume allows the volume to be added or removed from an active SRDF/A SRDF group using either a create, delete, or move operation without requiring the other volumes in the SRDF group to be suspended prior to the operation. Remote TimeFinder/Clone restore to SRDF R1 The feature that has existed in previous versions of the Enginuity code has been enhanced in Enginuity 5874. The feature now allows the R2 volume of a TimeFinder/Clone setup to be used to perform a SRDF restore to its partnered R1 volume while a TimeFinder/Clone restore is in progress to the R2. SRDF/Star with an R22 device The R22 device is a new SRDF volume type introduced in Enginuity 5874. A concurrent R2 (R22) volume is one whose two remote mirrors are paired with a different R1 volume. However, only one of the R2 mirrors may be receiving data from its corresponding R1 volume at any given time. The primary intended use for an R22 volume is to simplify failover situations and improve resiliency in SRDF/Star environments. With the introduction of the R22 volume the need to create recovery volume pairings during SRDF/Star setup is negated. The relevance of the SRDF enhancements in VMware Virtual Infrastructure environments is described in the TechBook Using EMC Symmetrix Storage in VMware Infrastructure and vsphere Environments, available on Powerlink. Additional capabilities RAID Virtual Architecture With Enginuity 5874, the RAID-X naming changed to RAID Virtual Architecture (RVA). RAID Virtual Architecture (RVA) extends the Enginuity 5773 RAID 6 design to support all current RAID types in a single back-end engine. It is not a new RAID protection level in that you still have unprotected, RAID 1 (mirrored), RAID 5, and RAID 6 as before. CKD RAID 10 is still four RAID 1 devices grouped together with metastriping. RVA does hide the back-end management of the RAID groups. Now RAID protection is associated with individual mirrors of a device and not the whole device itself. RVA is an enabling technology for Symmetrix that has been used to implement other features such as enhanced Symmetrix Virtual LUN migrator (discussed earlier), and the expectation that it will be used with other features in the future. Applied Technology 10
Conclusion The Symmetrix VMAX introduces a number of new hardware features such as the scalable fabric interconnect design that allows the storage array to seamlessly grow from an entry-level configuration into the world s largest storage system. A DB2 for z/os database environment backed by the power and flexibility of the Symmetrix VMAX marks a new standard for storage environments. The Symmetrix VMAX provides improved performance and scalability for today s and tomorrow s demanding enterprise storage environments, allowing for far-reaching growth. The Symmetrix VMAX storage controller running Enginuity operating environment version 5874 when used in conjunction with Mainframe Enabler 7.0 provides many new features and functionality, including Enhanced Virtual LUN Technology, to improve data center efficiency and improve the ROI of DB2 systems deployed in this environment. Applied Technology 11