Technical Description

Transcription

1 Technical Description EonStor F16F Fibre-to-Fibre RAID Subsystem Introduction Infortrend Technology, Inc. RAID Controller and Subsystem Specialist The EonStor Fibre channel RAID subsystem provides unprecedented level of performance, availability, and configuration flexibility. There are currently five models in the EonStor F16F family, including RAID subsystems powered by single or dual-active RAID controllers, and two JBOD enclosures each supporting the connectivity of 16 hard drives. The EonStor series is an ideal solution addressing the storage needs of today s mission-critical applications in terms of configuration flexibility, data availability, and serving as the information backbone of an enterprise. Downtime is not an option for those 24/7 availability applications. Designed to eliminate all possible causes of downtime, all of the EonStor s key components are hotswappable. It is designed to deliver high throughput rate, and to store and protect data in environments where storage is shared across network. As depicted by the following examples, high availability requires seamless integration between hardware and firmware functionality. The subsystem is capable of discovering and repairing parity inconsistency or media errors while rebuilding a logical drive.

2 Firmware of a dual-active system can be upgraded online. Each of the RAID controllers takes turn shifting I/Os temporarily to its partner, resets itself, and completes the upgrade process. Highest level of data availability is assured even when the array is operated under a degraded situation. Connectivity Optimization Expansion Expansion by Cascading The EonStor comes with dual-channel FC-2G connectivity to host and a FC-2G dual-loop linking dual-ported drives in the subsystem s sixteen drive bays. Firmware has embedded optimization schemes that suit varying applications with performance demands either on high I/O rate or high throughput per second. Array stripe size, caching policy, and numerous performance-related features are configurable on a per logical drive basis. Subsystem default configurations, such as stripe size and channel mode parameters, can also be adjusted before shipping to different customers using a proprietary program. Another of Infortrend s extraordinary features takes advantage of the rapid increase of hard drive capacities. Thanks to the rapid growth, expansion of an array requires no additional drive enclosure. Additional capacity can be added by replacing the original member drives with larger drives. Data is then re-striped across the new drives. The whole process is completed with active host I/Os and can be performed simultaneously with multiple new drives. Capacity expansion by adding drives is also supported. The subsystem series includes two JBOD models based on the same reliable enclosure design, each using single or dual SES modules. When a JBOD is cascaded with a running RAID subsystem, its status is immediately polled and it automatically becomes a member of the managed arrays. Each F16F RAID subsystem can be cascaded with up to 7 drive enclosures. Its modular design allows easy expansion to over 26TB of capacity by stacking enclosures. Four expansion SFP sockets on each enclosure enable high flexibility for complex storage connections.

3 Figure 1 RAID System and Cascaded JBODs Variants Model Name Application EonStor F16F Family Chart Single RAID controller EonStor F16F-S2A2 RAID subsystem Redundant RAID controllers EonStor F16F-R2A2 EonStor F16F-R2A2-A Single S.E.S. module EonStor F16F-S2J2 JBOD enclosure Dual S.E.S. modules EonStor F16F-R2J2 The R2A2-A model comes with controllers that provide 6 FC channels. Table 1 EonStor F16F Family Chart The RAIDWatch manager software controls the EonStor subsystem via the host connections (in-band protocols) or the Ethernet network. It is rich with configuration options featuring remote management and the ease of use by graphical look-and-feel. RAIDWatch supports centralized and global management. It is a Java-based program compatible with nearly all operating systems and runs from any networked location. The software manages all administrative tasks, including array configuration, host LUN mapping, performance tuning, etc. All of the configuration tasks is performed with no interruption to ongoing I/Os.

4 Multiple instances of the GUI manager can be installed and run on computers over the network. Multiple arrays can be managed by a running GUI manager. Switching between the status windows of different arrays takes only a single mouse click. Its sub-modules, Event Monitor and NPC, can be installed on different computers and run simultaneously as separate software sessions. If one computer or part of the network should fail or is disconnected, there is no blind time to the array status. Disk Drive Configuration Physical disk drives in the array can be grouped into multiple logical drives, each with a different RAID level. Several logical drives can be striped together to form a logical volume, or partitioned into smaller, more manageable capacities. In heterogeneous environments where a single array is accessed by servers running different OSes and operating with various performance requirements, these capacities are made available to the storage network, each with unique access restrictions and optimization patterns. ID/LUN combinations can be associated with a logical drive, a logical volume (a group of logical drives), or a logical partition of them.

5 Section 1 System Overview Figure 2 System Modules The system comes in a standard 3U, rack-mountable enclosure. All its serviceable components are accessible either from the front or rear side. It is mounted onto a rack cabinet using the mounting holes on the sides and through that on the forearm handles. The system s major functionality are described as follows: 1. The F16F RAID subsystem houses one or two RAID controllers in a single or dual-active configuration, supports the connection of sixteen, 1-inch profile hard drives. 2. One F16F RAID subsystem can supply an enterprisescale deployment site with massive capacity brought by the building blocks of multiple JBODs. Saving expansion costs is one of its benefits. Starting with an affordable configuration, new enclosure(s) can be added should the need arise for more capacity, or that host connection can be reconfigured without affecting the currently active I/Os. 3. EonStor s configuration flexibility is unmatched in the industry. Hard drives can be grouped into different arrays of different RAID levels, managed by different RAID controllers, and each operating with separate optimization pattern. 4. Combined with appropriate multi-path drivers on the host computers, the RAID controller modules are fully faulttolerant. Controllers can failover or failback without user intervention, totally transparent to the host. All key

6 modules in the system are hot-swappable to ensure the highest availability. 5. All signal paths are routed between the dual-redundant RAID controllers over back-end PC boards. A mid-plane receives power supplies, RAID controllers, cooling fans and other modules that are accessible from the back-end. A drive backplane connects 16 hard drives on the frontend via SCA-II connectors. In the event one module fails, the failed module is automatically disconnected and the existing modules gain access over the common backplane to continue servicing I/Os. There is no active component on these PC boards. 6. The F16F is designed for path and module redundancy. I/Os are directed through the surviving path in the event of host port disconnection or component failure. Section 2 7. The subsystem is configured locally through a DB-9 RS- 232C serial port; or remotely over an Ethernet port. Each controller s Ethernet port can be attached to local LAN hub. In the unlikely event of controller failure, port IP is inherited by the surviving controller for continuous monitoring through RAIDWatch manager. The RAID Controller Controller Hardware The RAID engine inside the controller unit(s), IFT-5251F, evolved from Infortrend s sophisticated external controller design and is powered by a robust firmware. The RAID controller is housed in a 1U height canister. The canister contains the controller main board and a second-level PCB providing additional logic (e.g., battery charger circuits, Ethernet chipset) and signal paths to the hot-pluggable connectors on the back-end. The canister has an ejector handle to ensure positive insertion and smooth removal of the module. The controller is designed for dual-active redundant controller operation featuring 2Gb/s Fibre channel end-to-end connectivity.

7 Bandwidth & Capability The controller is at ease with handling large sequential throughput with its 64-bit, 133MHz memory bus for a total of 1066MB/s bandwidth. The bandwidth derives from its dual- PCI bus design. I/Os are distributed over two separate data paths; one is dedicated to I/O data transfer and the other to CPU access. Parity calculation is handled by dedicated XOR ASIC chipsets, contention for memory is minimized. As for random and smaller I/O transactions, the 256KB L2 in controller s PowerPC CPU accelerates quick I/O turnaround. SAN connection is supported with point-to-point, F_port, and FL_port connectivity. Each of the FC-2G host ports is capable of 200MB/s throughput. Host-side connection is provided through two SFP sockets on each controller, four total on the dual-active controller models. This makes cross-linking an easier task from host ports to (among) multiple servers, FC hubs, or fabric switches. The connection to enclosure drives are routed over two FC- 2G channels in a redundant dual-loop. External interfaces to the drive loops are provided as four SFP connector sockets on the enclosure s rear panel. Each of these sockets contains a short-wavelength optical transceiver for optical wire linking. The bypass functionality is enabled by default on enclosure drive loops and the drive loop expansion ports. This ensures redundant access to drives without the use of an external Fibre channel hub. The bypass functionality for the host ports is userconfigurable through DIP-switch jumpers on the system rear panel.

8 Section 3 Design and Functionality The Bypass Functionality The onboard hub for host ports is provided on models equipped with redundant RAID controllers, i.e., the EonStor F16F-R2A2 and F16F-R2A2-A. Figure 3 Host Port Bypass When the onboard hub is enabled through jumper switch: 1. The signal paths between the same I/O channels on the two partner controllers are connected. 2. The PBC (port bypass circuit) functionality on host loops is enabled. If bypass is functional (see Figure 3 Host Port diagram on the upper left), channel 1 of controller A and channel 1 of controller B will be looped together. The same channels on the counterpart controllers will be combined into the same host loop. Three more points to be considered with bypass functionality: The host ports on the two controllers assume the same WWN node name and different port names. A unique ID that can be manually configured ensures that WWN conflicts will not occur. If a controller fails, the surviving

9 controller will avail itself using the failed controller s port names. In the event of cable disconnection or RAID controller failure, a valid data link through the existing controller will continue data transfer that was previously served by the failed controller. I/Os are re-routed down the surviving link to continue data access. If the host ports are connected to the F_ports on FC switches, then the bypass functionality should be disabled. SAN-Related Functionality The EonStor F16F supports all necessary algorithms for sharing storage in multi-host and multi-os environments. Capacities can be shared as virtual volumes and that efforts have been made to ensure system can co-work with most 3 rd party management software. WWN seed read from subsystem Customizable INQUIRY serial number data to enable clustering implementations. LUN Filtering Mapping (SAN Mapping; see details in the following section) Point-to-point or Fabric host channel connectivity allowing each channel to achieve maximum bandwidth Support for multiple, redundant host data paths and automatic load balancing SCSI-3 Persistent Reservation support for clustering applications

10 LUN Filtering Figure 4 LUN Filtering (SAN Mapping) Infortrend is among the very first to provide the LUN Filtering capability for SAN environments. LUN Filtering uses the WWPN port names on host adapter cards (HBA) to recognize host computers. Various filtering entry parameters are then added to a WWPN entry: 1. A manually-defined masking value is applied to specify an ID range. It functions like the routing table entries on a LAN or WAN. 2. Include/Exclude: the ID range can be used to include or exclude one or more servers from accessing specific logical units of the array. 3. Access Mode: this entry can further specify host computers as having the full access or the read-only access. 4. Various entry parameters are saved in a WWN table. This table is maintained in NVRAM as part of the controller s configuration. 5. Each entry or host HBA WWN can be assigned a nickname for ease of configuration.

11 6. Multiple filtering entries can be associated with a logical unit (any logical configuration of array capacity) for clustered or shared storage deployments. Intelligent Caching Algorithms The subsystem supports data cache in one DIMM module; two rows, 512MB maximum per row for a total of 1GB memory size per RAID controller. The subsystem firmware has intelligent cache management that supports write-back cache and advanced caching algorithms described as follows: 1. Sorting of cache buffers prior to cache flush operation 2. Gathering of writes during flush operation to minimize the number of I/Os required for RAID parity update, minimizing use of system resources and disk spinning activity. 3. Two basic optimization modes: Optimization for Sequential I/Os & Optimization for Random I/Os 4. Elevator Sorting and Gathering of drive I/Os 5. Support for multiple, concurrent drive I/Os (tagged commands) 6. Intelligent, predictive, and multi-threaded read-ahead 7. Support for multiple and concurrent host I/O threads (hot command queuing) Caching algorithms are designed to provide optimum performance for either large/sequential or small/random accesses. Together with the tunable optimization schemes for individual arrays, disk performance can be adjusted to a per- LUN precision.

12 Array Expansion Both of the system s logical configuration types (logical drives or logical volumes) can be expanded not only by including additional drives, but also replacing small or obsolete members. When new capacity is added, the original LUN-array association is not affected. The additional capacity is useful when associated with additional LUNs. The second expansion mode, as diagrammed below, copies the existing data on the members to the new and larger drives. The key benefit of this method is that no additional drive bays or canisters are needed. Use an empty drive bay or replace the spare with a larger drive to proceed with the expansion. If more bays are available, expansion can be executed simultaneously on multiple drives. Except for the bandwidth required for this task, no interruption to the host I/Os is to be experienced when commencing array expansion. Figure 5 Array Expansion: Mode 2, Copy and Replace

13 Write Policy Two caching modes, Write-back and Write-through, are available for performance optimization. Only write caching is configurable in Infortrend s RAID subsystems. The Read requests are automatically managed by controller firmware. Firmware-embedded write optimization, Gathering and Sorting, method as described in the previous section. Cache Protection Data cached in a redundant controller system is constantly synchronized between partner controllers, over the dedicated communications channels. The 4-channel model, F16F-R2A2, distributes the communications traffic across the back-end drive loops. The 6-channel model, F16F-R2A2-A, provides higher transfer speed using two FC-AL loops dedicated to data cache synchronization. There are two more points to consider with data cache synchronization: The synchronization operation consumes system resources and can be manually disabled for better performance if the Write-through mode is preferred on a redundant controller system. Each controller also maintains an exact replica of its partner s configuration data. The controller configuration data, including that of LUN mapping scheme and array parameters setting, is synchronized between the controllers. This makes two controllers exactly the same and always ready for replacing a failed partner. The synchronized cache function and battery module protects unwritten data during controller failure or power outage. In the unlikely event of controller failure, the surviving controller can take over the write operations. There is no

14 Controller Failover need for user s intervention or re-configuration after a controller failback or power restore. Infortrend s Redundant Controller design lets two controllers assume the roles of either the Primary or Secondary controller. During normal operation, the Primary controller manages all requests for data. In the unlikely event of controller failure, say, if the Primary controller fails, the Secondary controller assumes the role of the Primary and continues servicing all IO requests. The dual-controller models come standard with a battery module installed in each of its controller units. A battery module contains two Li-ion battery cells. Depending on the level of redundancy required, a battery module can be selected for the single-controller system. The battery module can sustain 1GB memory size of cached data for up to 72 hours. System Protection and Cache Flush Operation To protect system hardware from extreme environmental conditions, the system can commence an auto cache-flush and automatically shuts down on preset conditions. The system commences a cache flush upon the discovery of the following conditions: RAID controller failure (dual-active mode) Battery charge low or failure Power supply failure Cooling fan failure Temperature exceeding preset thresholds

15 More remarkable is that the environmental thresholds can be manually adjusted, if the preset values do not match the requirements of the installation site. JBODs (Drive Enclosures): EonStor F16F-S2J2 EonStor F16F-R2J2 The JBOD enclosures provide the connectivity of a fullduplex dual-loop across the 16 drives installed. Using the same components as its RAID system counterparts, all the primary components of the enclosures are hot-replaceable. They include the disk drives, cooling fans, power supplies, and the SES monitoring unit(s). The SES devices pass component status information through multiple disk drives. The expansion ports on the rear panel are equipped with bypass circuits to ensure loop integrity. The bypass function on each expansion port can be disabled using the enclosure DIP switch to ensure a broken link will not be automatically healed and therefore is immediately acknowledged by the host or RAID system. Multiple JBODs can be cascaded with a RAID subsystem up to a maximum of 7. Enclosure Monitoring SES Implementation The enclosures support off-the-shelf disk drive types with different capacities and rotational speeds. RAID subsystem: Modules and related sensors within a RAID system model are interfaced to its RAID controller unit over an I 2 C bus. JBOD: One or two S.E.S. modules provide access to monitor / control all enclosure elements. These modules handle the status report of all JBOD elements including drives, power supplies, cooling, and temperature. The RAID controller firmware handles drive failure.

16 SES is implemented using the pass-through method. Depending on the number of SES modules, up to four (4) drives can be used as the alternate paths from firmware to SES devices. Section 4 Configuration There is literally no limitation on the number of drives to be combined into a logical array, the stripe size, RAID level, or the locations of its member drives. As long as the I/O hits stay reasonably within the channel bus bandwidth, and the drives equally configured, the capacity of an array can support a heterogeneous configuration of servers with varying I/O access characteristics. Cabling The subsystem models come powered by single or dualactive controllers. Between the two dual-active controller models, the only difference is the extra channels used for controller communications. The communications channels are strung across a common backplane between the controllers and no user configurations are required. Cabling the subsystem is mainly concerned with connecting to host platforms and cascading JBODs. Fibre channel connection is provided through industry-standard, 2Gb/s LC type SFP sockets that work with short-wavelength optical transceivers. Use of copper is possible, but is not considered an optimal choice. Rear Panel Components: Dual-Active RAID Model Figure 6 RAID System Rear View

17 Rear Panel Components: JBOD Enclosure Figure 7 JBOD Rear View Host ports are accessible from the enclosure rear. There are two SFP ports on each controller s face plate. Depending on the host applications, the port bypass function can be manually configured. Each series model (JBODs included) has another four SFP sockets in two hot-swappable modules for drive loop expansion. Single Controller: Direct Attachment Figure 8 Single Controller Direct Attachment Single Controller: Via Switch Figure 9 Single Controller Via Swtich Configurations using single RAID controller do not provide board-level redundancy.

18 Dual-Controller: Direct Attachment Figure 10 Dual-Controller Direct Attachment This configuration provides: 1. Data path redundancy for dual-active controllers 2. Loop by-pass via the onboard circuits. No need for an external hub. Dual-Controller: Via Switch Figure 11 Dual-Controller Switched Fabric This configuration provides data path redundancy for dualactive RAID controllers. Loop by-pass resiliency is provided by external FC switches. When connected to F_ports on FC switches, the onboard hub is disabled.

19 If multiple host IDs are used, the connection to switch ports should be configured to operate in FC-AL mode. Connection from switch ports to host HBAs can operate in the point-to-point mode. It is essential to implement SMP (Symmetric Multiprocessing) software and that the software should be able to find an alternative access to array capacity in the event of controller or path device failure. Array Configuration Logical Volumes (Multi-level RAID) Disk Level Protection Configuration of multiple hard drives into logical arrays of different RAID levels. RAID levels supported: RAID 0, 1(0+1), 3, 5, 10, 30, 50, and JBOD RAID0: Disk striping RAID1: Disk Mirroring; RAID0+1: Mirroring plus striping, this level is automatically applied when more than two drives are selected for a RAID 1 array RAID3: Disk striping with a dedicated parity disk RAID5: Striping with interspersed parity RAID10, 30, and 50: Logical Volumes (Logical Drive Striping) These are striping combinations of two or more logical drives. Firmware allows striping of logical drives with different RAID levels, enabling flexible options with combining configured capacities. The configuration of a logical drive is often confined by the sustained transfer rate of drives and data bus. Logical volume avoids the consideration by grouping multiple logical drives. Each logical drive maintains its unique I/O characteristics. If host accesses a logical volume containing multiple logical drives, the I/O traffic is distributed to the data buses where members of these logical drives reside. This allows the administrators to combine or reconfigure massive capacities. For example, a RAID5 logical drive and a RAID 0 logical drive can be combined to form a logical volume. This flexibility obscures the RAID level definition of logical

20 volumes. A logical volume can consist of logical drives of different levels. It is when a logical volume consists of members of the same level that the volume s level can be named. Two or more RAID 3 logical drives can be included in a logical volume, and the logical volume is called a RAID 30 array. RAID level 0 1 (0+1) 3 5 Capacity N N/2 (N>1) N-1 N-1 Data Reliability None >> RAID5 >> NRAID sustains single drive failure >> NRAID sustains single drive failure Performance R: Highest R: High R: High R: High Sequential Performance Random W: Highest R: High W: Highest W: Medium R: Medium W: Low W: Medium R: Medium W: Low W: Medium R: High W: Low Logical Volume: Benefits Logical volume configuration can be considered as a multilevel assembly of drives. A logical volume provides higher reliability than a logical drive for the following reasons: 1. Every logical drive in a logical volume can have its dedicated hot-spare. Using more spares in a logical configuration decreases the risk of multiple drive failure. 2. The mean time between failures is larger because it takes a much shorter time to rebuild a failed drive in a small logical drive that is a member of a logical volume. It takes longer to rebuild a large, monolithic logical drive. If yet another drive fails during the rebuild process, irrecoverable data loss will occur. A logical drive containing 16 drives stands higher risk of fatal failure than each of the smaller members of a logical volume. The idea is shown in the diagram below.

21 Figure 12 Logical Configurations Array Partitioning Other data availability features include: Data Availability Features Dedicated and Global spare drive support Automatic rebuild onto hot spare Background logical drive rebuilding RAID parity update tracking and recovery Recovery of data when bad blocks are encountered on reads Automatic drive bad blocks reassignment on writes RAID parity checking and regeneration Background drive physical Media Scan Bad block handling in degraded mode and during rebuild Optional write-verification for normal writes, rebuild writes, and logical drive initialization Power-failure and bad-drive handling during Add-Drive expansion SMART detection of imminent drive failure followed by the commencement of drive cloning operation Parity synchronization in redundant controller write-back mode to avoid write-holes

22 Block Level Protection Block Level Protection The occurrence of bad blocks or inconsistent parity on more than one member drive may invalidate the whole array. The proprietary Intelligent Drive Handling compares, recalculates array parity, and then rewrites data to drives. In the degraded mode, data that could not be regenerated from damaged blocks is abandoned and the rebuild continues. Those irreparable disk blocks are considered as invalid by the host computers. This ensures access to the majority of array data when media errors occur. Supported Array Features: Array variable stripe size: Configurable from 4KB up to 256KB per logical drive Preset optimization schemes The system optimization modes (Random/Sequential) have preset values associated with stripe size of arrays created in different RAID levels. Using the default value should be sufficient for most applications. Opt. for Sequential I/O Opt. for Random I/O RAID RAID RAID RAID Figure 13 Array Optimization Settings 64-bit LBA support: Up to 64 terabytes of capacity can be included per logical drive Up to 128 physical drives per logical drive Up to 128 logical drives and 32 logical volumes (logical drive striping) per RAID system configuration Up to 64 partitions per logical drive/logical volume Up to 1024 LUN numbers for host mapping (1024 configurable through the proprietary Iappend program) Immediate array availability:

23 Data can be immediately conducted onto a newly created array and the array initialization is completed in the background later when there are more system resources. Cache write-policy configurable per logical drive: Write-back/Write-through caching mode Host LUN Mapping Figure 14 Host LUN Mapping An application host sees storage capacities as the logical devices identified by its channel bus ID/LUNs. Each of the capacity volumes (as diagrammed above, configured as logical partitions) is presented over the host-side connections as the combinations of host channel IDs and LUN numbers. Firmware supports flexible, any-to-any association between capacity volumes and host ID/LUNs via all configuration utilities. I/O Characteristics Determinants When accessed by host, the I/O characteristics of these capacities are determined by the RAID level, stripe size, number of member drives (stripe width), or the write-policy they are configured with. The subsystem supports unparalleled flexibility with the configuration of the following:

24 RAID Level Stripe Size 1. RAID levels have enormous effect on array performance. For example, a RAID 5 array has comparatively low performance when applied with multi-threaded small writes. The subsystem provides complete options with RAID levels. Different RAID levels can co-exist in the same system or in the same logical volume. 2. Stripe size is user-configurable on a per array (logical drive) basis. Note that only by testing different stripe sizes with different applications can an optimal stripe size be determined. Stripe size is configurable on a per logical drive basis. It determines how files are sliced into smaller pieces, how many drives a file will take to contain its data blocks. File size and host access behaviors determine the stripe size to be chosen for each array. Hard Drives Configuration with Drive Enclosure(s) Array Characteristics Workload Balancing 3. Number of drives in an array (stripe width): more drives in an array means data can be written to or read from more drives simultaneously. There is no limitation on the locations of drives, within one or multiple enclosures. As many as 128 hard drives can be included in a logical drive, actually surpassing the limitation on physical connection (when 7 JBODs are cascaded with one RAID subsystem, each containing 16 hard drives). 4. Grouping drives from different JBODs can help balancing workloads and providing increased redundancy. Using the dynamic expansion functionality, drives in a new enclosure can be easily integrated with the existing array while it remains online and accessible for I/Os. 5. Array characteristics can be fine-tuned to fit specific application needs including the stripe size, write-policy, name of an array, and LUN filtering (SAN mapping) entries. 6. Logical drives or logical volumes can be individually assigned to different RAID controllers, thus splitting the workload in a redundant controller configuration. Adjusting these determinants enables a storage system to satisfy the varying demands of multiple servers in a heterogeneous environment.

25 Configuration on Disk Drives When configured into arrays, each member of an array will have a 256MB of disk space formatted with a metafilesystem. This disk space is unseen by the host or users and is reserved for storing the array configuration data and nonvolatile event logs. Though not an operation recommended for users, drives can be relocated in a different system/enclosure while data remains intact. Section 5 Management Software RAIDWatch Management Software The RAIDWatch management software is a Java-based GUI array manager designed for administering all Infortrend s subsystems and external RAID controllers. When run on a remote computer, a remote session is available by downloading Java Applet across the network using a standard browser. Except for the requirement on browser s support for Java, it has almost no limitations on remote configuration. RAIDWatch supports the configuration of all RAID configuration options with graphical presentation of array elements and easy-to-use look and feel. Non-disruptive Management Software The management software accesses the array via in-band connection (Local) or an out-of-band Ethernet port (Network). All configuration tasks or maintenance operations can be completed while the storage is servicing I/Os. RAIDWatch s major configuration options include: Online Array Expansion (two dynamic modes) Array Configuration and Partitioning Array initialization and host LUN mapping Configuration parameter tuning Enclosure component monitoring Array optimization setting Real-time array status via Event Monitor Status notification via , fax, LAN broadcast, etc. (NPC - Notification Processing Center) Management of multiple arrays through IP sessions

26 The RAIDWatch software is ideal for managing Infortrend arrays in a heterogeneous environment where protection of data and management of array can be accomplished using a single software installation. The RAIDWatch software runs on a host computer or a PC used as management station and can manage all SCSI or SAN-attached arrays through different IP sessions, regardless of their physical locations. Managers installed on different computers can run simultaneously allowing technicians at different locations to diagnose a problem. SSL (Secure Socket Layer) is supported so that RAIDWatch can securely manage the data transmitted between management browser and the arrays. Other important functionality include: A comprehensive enclosure view, showing a map of hardware components and its related configuration. Component failures can be easily identified. Configurable event messages and maintenance of a list of contacts for event notification.