A look at how Inyo (VNXOE 32) optimizes a VNX configuration

I previously discussed EMC’s new release of code for VNX here.   As I catch up on writing blog articles following my wedding last month, I thought I’d highlight one real customer situation that I was working on in August where the improvements saved a considerable amount of money, increased the usable capacity percentage, and offered greater IOPS capability.   This is a modification of an email I sent to the customer explaining the changes I made in the configuration. 

The previous config consisted of a VNX5300 with 37 SAS drives and 31 NL-SAS drives.   The new config consisted of 37 SAS drives and 33 NL-SAS drives.

In short:

• The previous config required the storage pool to use RAID6 for all drives, which is needed for the high-capacity 7200RPM drives, but is a bit overkill for 15K drives and reduces usable capacity on those drives.     This new config is able to support mixed RAID types in the same FAST storage pool.  

 

• EMC has now blessed new RAID layouts as best-practice.    Underneath the storage pool covers, the 15K drives use an 8+1 RAID5 protection scheme instead of 4+1, and the 7200RPM drives use 14+2 RAID6 instead of 8+2 (Note: the default previously was 6+2 but there was a workaround documented by penguinpunk here to use 8+2, which I’ve confirmed with EMC still works).  It is still presented as a single storage pool. 

 

• The previous config offered 110TB Raw and 76TB Usable, or 69% usable.   The new config is 100TB Raw and 76TB usable, or 76% usable.  
  • The previous config offered  12TB usable on the 15K tier and 64TB usable on the 7200RPM.   The new config is 13TB usable on the 15K tier and 63TB usable on 7200RPM.

 

• The new config offers 6,300 IOPS from 15K, 2,880 from 7200RPM, and 7,000 IOPS from FAST Cache, for a total of 9,180 IOPS.   The previous config offered 6,480 IOPS from 15K and 2,700 IOPS from 7200RPM for a total of 9,180 IOPS (same number).  
  • Though this is the same number of IOPS, the new config will offer more effective IOPS because there will be less IOPS consumed by RAID6 parity calculations on the 15K drives.

 

• The storage pools will now automatically load-balance within a tier if there is a hot spot within a 8+1 or 14+2 RAID group.  In other words, if one of the 8+1 R5 groups in the storage pool is running hot, it will move slices of data as needed to a less busy 8+1 15K group of disks. 

 

• If you add drives, the VNX will now automatically re-balance all existing data across all the new drives to increase performance for existing data in addition to adding new capacity.     

 

There are still some things I’d like to see improved in terms of how pools work on VNX, which I have a feeling won’t come around until VNX “2”, regardless there’s lots of great stuff in this code release that gives the VNX a considerable boost in its market relevance.