EMC VNX2 Storage Array Review

VNX is EMC’s unified enterprise storage solution for block and file. The latest release called VNX2, uses the advanced Intel Sandy Bridge processor with more cores. It also has more memory (RAM).

It’s Fast VP technology which dynamically moves data between SSD (flash drives), SAS drives and NL-SAS tiers, is now improved by decreasing the data “chunk” from 1GB to 256MB, which allows greater efficiency of data placement. Also, using SSD as the top tier is new in VNX2.

It’s Fast Cache technology has also been improved. Per EMC, “the warm up time has been improved by changing the behavior that when the capacity of FAST Cache is less than 80% utilized, any read or write will promote the data to FAST Cache.”

VNX2 boasts of its active/active LUNs configuration. However, active/active LUNs only work when the LUN is provisioned using RAID Groups. It does not work with Storage Pools. Hopefully, active/active LUNs will be available for Storage Pools in the future because more and more LUNs are being configured using Storage Pools instead of RAID Groups.

Another improvement is that in Unisphere, storage administrators do not need to set the storage processors (SP) cache settings – read and write cache settings and high and low water marks. It needs only to be turned on or off. The system now adjusts the cache settings automatically.

There are also no hot spare drives now. You simply don’t provision all the drives, and a blank drive becomes a hot spare. You can set the hot spare policy for each type of drive. The recommended is 1 per 30 drives.

I noticed a couple of shortcomings in this release. I do not like the fact that when creating a LUN in a pool, the “thin” is checked by default now. I believe that thick LUNs should be the default because of performance considerations. In addition, if storage administrators are not careful, they may end up over-provisioning the pool with thin LUNs.

On the file side, there is really no major improvement. I believe there is no updates on the data movers. Data movers still function in active/passive mode. One change though is that you can now use VDM (Virtual Data Mover) for NFS, although to configure this, you need to use the CLI.

Overall, VNX2 is one of the best enterprise storage array in terms of its performance and functionality.

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