Author: Matt Trottier, Principal Consultant
EMC World 2010 stormed through Boston this year, where EMC made its case on why it should be the storage architecture driving your private cloud initiative. EMC released many new products and new feature sets to their existing product lines to further prove its case. During my time at EMC World, I had the chance to attend many of the technical breakout sessions. One I found particularly interesting was on the enhancements coming to the CX4 line in the upcoming months.
Thanks to the new 64 bit architecture of the CX4 line, EMC is able to bring some well needed feature updates to the Clariion via upcoming release of FLARE 30. FLARE 30 will expand on its storage pool technology, virtual provisioning, reintroduce it's FAST technology, give us our first common interface for CX, NAS and RecoverPoint SE, and find more useful ways to improve performance with Solid State Drives (SSDs).
Virtual Provisioning came out in FLARE 28 with EMC's initial attempt bring thin provisioning into the CX4 product line. In a nut shell, they allowed you to build storage pools from either FC or SATA disks to present Thin LUNs and overprovision storage. Under the covers, it was making a bunch of meta-luns spread across hidden RAID groups that made up the storage pool. What it did well was break the "brick and mortar" approach that had dominated EMC's way of thinking in terms of allocating and provisioning storage for years, and bring some sense of virtualization to the CLARiiON line. But it was severely limited since it could only support RAID 5 or RAID 6 and EMC did not recommend it for mixing high workloads across different host machines.
In FLARE 30, EMC has revamped virtual provisioning feature to become the new way to provision storage on the Clariion going forward. Here are some of the highlights:
- Pool size and drive count restrictions have been updated to support all drives in the CX4 minus the 5 FLARE drives. Essentially, this means you can build a 955 drive storage pool on a CX4-960 if you want.
- All drive types are now supported in the same storage pool including solid state disks (needed for FAST as explained below).
- RAID 10 can now be used for storage pools to allow for pools to accommodate higher write workloads.
- Thin provisioned LUNs will now be able to expanded or shrunk in a single step without having to build a meta-lun.
- When provisioning LUNs from a storage pool, LUNs can be created as "thick," meaning all space is reserved for the size of the LUN in a contiguous address space.
You will still be able to use traditional RAID groups if you want for specific use cases, but in order to get the most out of your CX4, virtual provisioning storage pools are the way to go. Why? Because it is a great way of spreading I/O workloads across as many spindles as possible to get the most bang for your storage buck. Other storage vendors have been doing this for years in one form or another (NetApp, HP EVA, 3PAR to name a few). It only seems natural for EMC to finally start moving to virtual storage pools as that is what the market is asking for.
The other good reason for using storage pools is EMC engineering is going to start building new features that take advantage of their storage pool technology.
One such feature is Fully Automated Storage Tiering, or FAST. This will build upon virtual storage pools and allow data to be automatically placed into the proper storage tier (or disk type) at the sub-LUN level. The CLARiiON will move the 1 GB chunks of the thin LUNs to the proper storage type in the pool as those chunks "heat up" or "cool down."
To show how this works, consider the following scenario: Say I have a CX4-240 with a storage pool consisting of (5) 72GB SSDs, (30) 450 GB FC drives and (20) 1 TB SATA drives. I then provision a 500 GB Thin LUN to a host for a SQL database from that pool. As the SQL servers uses that LUN, the hot chunks of the most used SQL tables will be moved to the SSDs for high performance while untouched portions of the database will be moved to slower disk in the pool, either the FC or SATA drives. Over the life of the LUN FAST will continually tune the LUN and move 1 GB chunks to the appropriate disk type based on its "temperature."
FLARE 30 is also introducing compression for Thin LUNs in a storage pool. Traditional RAID group LUNs will be migrated into storage pools in order to support compression. Data compression will be a background process. EMC did state that this is intended to be used "relatively inactive LUNs," such as archive volumes, backup copies or static data repositories.
The last real interesting feature coming out in FLARE 30 is FAST cache. In simple terms, EMC will SSD drives as an extension to SP cache to help with overall storage performance. This will provide a much larger, scalable cache that can be turned on/off on a per LUN basis. Unlike the PAM card that NetApp uses in its filers to speed up read cache, FAST Cache can be used as either read/write cache, via RAID 1 or 10, or read cache via RAID 0. Depending on the CX4 model, FAST Cache will scale up to 2 TB of extended cache on the CX4-960. FAST Cache will support both traditional RAID group LUNs and storage pool LUNs.
FAST Cache is going give EMC an excellent way of making the high price of SSDs more palatable for the mid-tier market. Rather than trying to find that small table of an Oracle database that requires 6000+ IOPS to move specifically to SSDs, FAST cache has the potential to have an immediate impact on any customer's environment that needs a performance boost to extend the life of their current CX4.
Last, but certainly not least, EMC will be introducing a new unified management framework called Unisphere. Unisphere will be able to manage CLARiiONs, Celerras, and RecoverPoint/SE from the same management interface. Unfortunately, only Celerras with the new DART 6.0 will be supported for management in Unisphere. On the other hand, CLARiiONs with FLARE 19 and above will be supported. From what I have seen, EMC has taken great steps to make Unisphere more intuitive and easier to use than Navisphere or Celerra Manager. Going forward, as the product matures EMC will introduce additional management capabilities into Unisphere to manage additional EMC products.
