Enhancements to EMC Symmetrix V-Max systems is possibly around the corner (FY09 Q4).

FAST (Fully Automated Storage Tiering) is due this quarter and will be one of the most awaited software release in the enterprise storage space by EMC.

Bundled together with FAST, possibly a new microcode version the enables FAST (its associated features) and other expected enhancements.

Though this will be a major software release and functionality upgrade, I don’t think this would qualify as a 2nd generation EMC Symmetrix V-Max system.

But fully expect EMC to release its FAST v2 and V-Max Gen2 (possibly named like V-Max II or V-Max Ext) somewhere around Mid year 2010.

Here are a few new features to possibly expect on the EMC Symmetrix V-Max Systems this quarter.

1. Introduction of FAST v1, which should allow automated data movement within a single Symmetrix V-Max system. Here are some features of FAST as discussed on GestaltIT and by Barry Burke (TSA) on his blog.

2. FAST v1 data movement should possibly be policy driven around factors like time (how old is the data), SLA (promised SLA’s), Tier (from Tier 0 to Tier 1 to Tier 2) and possibly I/O or IOPS based.

3. FAST v1 should allow automated policy based data movement or prompt a user for manual intervention for data movement.

4. Do not expect FAST v1 to come for free, it will possibly be licensed based on the total number of TB’s in the storage subsystem.

5. Expect some integration between the IONIX platform and FAST v1 and possibly some very tight integration with future releases of FAST and IONIX.

6. Expect FAST and IONIX to integrate very tightly with Atmos through API’s and policies. We should expect to see this with FAST v2 and not with FAST v1.

7. So when does EMC retire Symmetrix Optimizer, with FAST v1 probably not, with FAST v2 probably yes.

8. 2TB SATA II drives will be introduced (According to a Keynote from Joe Tucci in NYC), though Joe Tucci didn’t mention what platforms the 2TB SATA II drives will be available on, it seems the V-Max upgrade would be the most logical platform.

9. The 2TB SATA II drive upgrade should make the V-Max 4 PB total storage (2400 drives x 2TB), possibly the single largest storage subsystem at an enterprise level.

10. RapidIO speed upgrade from 2.5 Gbps to 4 Gbps (interconnects between the engines) upgraded either through MBIE (new processors) and / or through microcode upgrades. EMC currently uses Serial RapidIO which supports 1.25Ghz to 3.0Ghz clocking speeds and can scale upto 10 Gbps I/O though EMC currently utilizes 2.5 Gbps as its interconnect speeds for the engines.

11. Increased drive interconnect speeds. May be denser EFD’s, though I can’t speculate on it.

12. FC and FICON (Host Connects) port speeds upgrade from 4 Gbps to 8 Gbps

13. Interconnect between two separate Symmetrix V-Max Systems (8 Engines each per system) expanding into possibly 16 (max) engines. The more I think about this concept, the more it makes me feel that there are no added benefits of this architecture, rather it will add more complexities with data management and higher latency. Remember how the V-Max was initially marketed with having hundreds of engines and millions of IOPS, the only way to achieve that vision is through interconnects. The longer the distance, the more latency with cache and I/O. If Interconnects end up making in this release, limitation on the distance between two Symmetrix V-Max system bays would be around 100 feet.

14. To the point above, another way of possibly connecting these systems could merely be federation through external policy based engines. Ed Saipetch and myself have speculated that concept on GestaltIT.

15. With the use of larger drive size, possibly expect a cache upgrade. Currently the Symmetrix V-Max supports 1TB total cache (512GB usable), which may get upgraded to 2TB total cache (1024 GB usable).

16. New possible microcode version 5875 that will help bring features like FAST, SATA II drives and additional cache into the Symmetrix V-Max.

17. Processors: 4 x Quad Core Intel processors on V-Max engines may not get an upgrade in this release, it should possibly be with FAST v2 as a midlife enhancement next year.

18. Further enhancements related to FCoE support.

19. Upgrade of iSCSI interface on Symmetrix V-Max engines from 1GB to 10GB (is now available with the Clariion CX4 platforms).

20. Really do not expect this to happen, but imagine RapidIO interconnects change to FCoE. Really not sure what made EMC to go with RapidIO instead of Infiniband 40 Gbps (which most of the storage industry folks think is dead) or FCoE with Engine interconnects, but if the engineers at EMC thought of RapidIO as a means to connect the V-Max engines, there has to be a reason behind it. Enginuity more or less doesn’t care about the underlying switching technology, making a switch from RapidIO to FCoE or Infiniband can be accomplished without a lot of pains. Though for customers already invested into RapidIO technology (with existing V-Max systems), it might be offline time to change the underlying fabric, which in most cases is unacceptable.

21. Virtual Provisioning on Virtual LUNs which is currently not supported with the existing generation of Microcode on V-Max systems.

22. Atmos currently is running as a beta release and we should expect a market release this Quarter. Should we expect to see an integration between V-Max and Atmos. I am not sure of any integration today.

23. A very interesting feature to have in the EMC Symmetrix V-Max would be system partitioning, where you can run half the V-Max engines at a certain Microcode level with a certain set of features and other half can be treated as a completely separate system with its own identity (almost like a Mainframe environment). Shouldn’t this be a feature of a modular storage array.

24. Symmetrix Management Console (SMC) and Vmware integration (like VMware aware Navisphere and Navisphere aware VMware). There is already quite a bit of support related to VMware in SMC for provisioning and allocation.

25. Also a much tighter integration between IONIX, FAST, SMC, Navisphere and Atmos may after all be the secret sauce, which would enable workflow, dataflow and importantly automation. Though do not expect this integration now, something to look forward for the next year.

Summary

Though I am still a bit confused on where FAST will physically sit.

FAST v1 can merely be a feature integrated within the Microcode, configurable & driven through policy within the Symmetrix Management Console.

FAST v2 (Sometime Mid 2010) should support in-box and out-of-box (eg: Symmetrix to Clariion to Celerra to Centera) data movement through policy engine.

Ed Saipetch and myself have speculated on GestaltIT on how that may work. Though after some thoughts, I do believe a policy engine can merely be a VM or a vAPP sitting outside the physical storage system in the Storage environment.

To promote the sales of the EMC Symmetrix V-Max systems, Barry Burke in his blog post talks about Open Replicator, Open Migrator and SRDF / DM (Data mobility) are now available at no cost for customers purchasing a new EMC Symmetrix V-Max system, these are some of the incentives that EMC is offering and further promoting the sales of its latest generation Symmetrix technology.

It remains to be seen the path of success FAST will carve for Symmetrix V-Max systems.

© Devang for Gestalt IT, 2009. | Enhancements to EMC Symmetrix V-Max Systems coming!!
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Typically look at a CX4-960, which can be scaled up to 960TB of raw storage and can have as many as 960 disk drives in it. With certain failure rates guaranteed, large number of drives can create a higher probability of failure. Every storage manufacturer these days includes some sort of hot sparing technology in the storage subsystems. EMC started offering this technology to its customers as Global Hot Spares. Then came an era where some value add offerings were brought in for proactive failures to minimize the chance of data loss. This brought to the table a technology that is termed as Proactive Hot Spares, where proactively failing drive is determined and global hot spare is kicked in.

I believe flare release 24 started offering Proactive hot spares. With this Flare release customers can proactively initiate a kickoff of hot spares through Navisphere or Naviseccli against a suspect drive.

Depending on the RAID type implemented, the RAID Groups can withstand drive failures and can run in degraded state without data loss or data unavailability. With RAID 6 implemented, a machine can have as many as 2 drive failures in the same RAID group, with RAID 5, a machine can have as many as 1 drive failure in the same RAID group, with RAID 1/0, RAID 1 a machine can have as many as 1 drive failure in the RAID group without data loss.

Drives supported on Clariion CX, CX3, CX4, AX and AX4 systems typically are FC (Fiber Channel), SATA II and ATA drives.

A Global Hot Spare has to be configured in an EMC Clariion system as a single RAID Group (with one drive). Once the RAID Group is created, a LUN should be bound as a Global Hot Spare before it could be activated.

The following is the sequence of steps that take place on a Clariion Subsystem related to Global Hot Spares (Supported on CX, CX3, CX4 systems)

1. Disk Drive failure: A disk drive failure in the system, Flare Code marks it bad.
2. Hot spare invoked: A preconfigured Global Hot Spare is invoked based on the Global Hot Spare selection criteria.
3. Rebuild: The Global Hot Spare is rebuilt from surviving raid group members.
4. Failed drive replaced: Failed disk drive is replaced with a good drive by a Customer Engineer
5. Copy Back: The Global Hot Spare copy has to finish before the new drive starts rebuilding. The rebuild or equalize happens in a sequential order of LBA (Logical Block Address) and not the LUNs bound no it.
6. Return Hot Spare: Once the sync of new drive is finished, the hot spare is invalidated (zero’ed) and put back in the Global Hot Spare pool.

The following is the sequence of steps that take place on a Clariion Subsystem related to Proactive Hot Spares (Supported on CX300, CX500, CX700, CX3, CX4). Proactive Hot Spares essentially use the same drives that are configured as Global Hot Spares.

1. Threshold of errors on Disk Drive: A drive gets hit with errors, it surpasses the number and type of those errors, and the flare code marks it as a potential candidate for failure.
2. Proactive Hot Spare invoked: Based on the potential candidate’s (drive) type, drive size and bus location a Global Hot Spare is indentified and the process is kicked off for data rebuild.
3. Potential candidate fails: Once the Proactive Hot Spare is synced, the flare code fails the indentified potential candidate.
4. Failed drive replacement: The failed drive is replaced by a Customer Engineer
5. Copy Back: From the proactive hot spare, the data is copied back to the newly inserted drive. The rebuilt or equalize happens in a sequential order of LBA (Logical Block Address).
6. Return Proactive Hot Spare: Once the sync of new drive is finished, the hot spare is invalidated (zero’ed) and put back to the Global Hot Spares pool.

The Global Hot Spares Selection Criteria:

The following are the criteria’s that are followed with selection (invoke) of a Global Hot Spare when a potential proactive candidate is identified or disk drive is failed. In the sequence listed below, Drive type is the first selection, Size of the drive is the second selection and location of the Global Hot Spare is the third selection. Speed of the drive (RPM) is not a selection criterion.

1. Type of Global Hot Spare Drive: As discussed above, Clariion Systems use three primary drive types. For FC and SATA II type drives, either or can be invoked against each other type. ATA drives can be invoked against an ATA drive failure.
2. Size of Global Hot Spare: Upon a disk failure, the drive size (Global Hot Spare) is examined by Flare Code. The size of failed drive is not the key in invoking the hot spare, but the total space of all LUNs (bound) on the drive is used as a determination criteria.
3. Location of Global Hot Spare: Based on the above two criteria, the location of the Global Hot Spare is considered as the third criteria. If the Global Hot Spare is on the same bus as the failed drive, it will be considered as the primary selection if the above two criteria’s are met. If the above two criteria’s are met and the drive is not on the same bus, then the Global Hot Spare is selected from other buses.

Other Considerations:

1. RAID Types: For the copy of data, with RAID 3 and RAID 5 data on the hot spare is built using the parity drive. With RAID 6 raid types, data on the hot spare is built using the RP (row parity) and / or DP (Diagonal Parity) depending on the number of failures in the RAID Groups. For the RAID 1/0 and RAID 1, data on the hot spare is built using the surviving mirrors.
2. Copy Times: The time required to copy or rebuilt a hot spare really depends on how large the drive is, the speed of the drive, the cache available on the drive, the cache available on the array, the type of the array, raid type and the current job processing on the array. Typical rebuilt times vary from 30 minutes to 90 minutes again depending upon how busy the storage subsystem is.
3. Global hot Spare types: For every 30 drives (2 DAE’s of drives), consider having 1 drive as a Global hot spare. Also verify, for every drive type (size, speed) in the machine, you have at least one configured global hot spare. Good idea to have global hot spares on various different buses and spread across multiple Service Processors.
4. Vault Drives: Vault Drives cannot be used for Global Hot Spares. The Vault drives are considered as the first 5 drives [ 0_0_0, 0_0_1, 0_0_2, 0_0_3, 0_0_4 ] on the Clariion System. If a vault drive fails, a Global Hot Spare takes over its position.
5. Rotational Speed: Rotational Speed of the Global Hot Spare is not considered before invoking it. It might be a good idea to have Global Hot Spares running 15K RPM’s potentially with large size drives.
6. Mixed Loop Speed: With certain Clariion Systems like CX3’s, available loop options are 4GB and / or 2GB and you can have a mixed loop speed in your machine, for hot spare selection the loop speed is not considered, in those cases it might be wise to have similar hot spares on both the 2GB and 4GB loops.

© Devang for Gestalt IT, 2009. | EMC Clariion Systems: Global Hot Spares & Proactive Hot Spares
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