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Storage pool on VNXe3200
Hi All,
I ran into a slight issue while deploying VNXe3200 that has a total of 12 x 600GB drives. The application will be VMware - two node cluster, where potentially there might be 10 VMs running, one of which will be Microsoft ERP NAV.
When configuring a storage pool consisting of 2 x R5 (4+1) (including the vault drives) I got the following warning:
'This option uses the system disks. The portion of the storage pool that uses these disks will have reduced capacity and storage resources in the pool may experience reduced performance.'
I know that it is a normal behavior from VNXe, but here it almost warns you that you are creating an imbalanced pool.
Best practices for VNXe does not have any recommendation whether to use the vault drives in the pool or not.
What is your take on this and what do you typically do for the VNXe arrays: do you or do you not use the vault drives as part of the storage pools? If you do or don’t use them, can you please explain why?
I am almost positive that I should not be using them, as it is unknown what it can lead to in the long run. It may work out well (depending on the IO pattern, which is unknown at this time) if the array is not busy, but may be bad if the array is hammered hard, and if there are performance issues. Then reconfiguring the pools may be another nightmare for everyone. So why not just avoid using them in the storage pools from the beginning.
Appreciate your input.
brettesinclair
715 Posts
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November 18th, 2015 03:00
The guidance really hasn't changed. Typically, you don't include vault drives as part of a Pool that has perfroamcne requirements, even though you can.
I keep them isolated, and make a standalone pool, for archive, iso's or low requirement workloads.
ZaphodB
195 Posts
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November 18th, 2015 07:00
I do not, as a matter of practice, use vault drives for user LUNs.
In your situation I would begin by cursing at whomever configured the unit.
With four vault drives and a hot spare you really only have seven disks for data/parity. There isn't really a 'best practices' sort of config for that.
If you go without a hot spare you could configure a pool with a single 6+2R6 group; that gives you a little over 3TBs of usable space in the pool, and while the R6 write penalty is unfortunate, it should not significantly impact performance given the size of the controllers, and the tiny number of disks. The additional fault tolerance of the R6 array pretty well balances out the lack of a hot spare.
If you require more capacity than the 6+2 affords you, refer back to the cursing part above...