StoreVirtual 3000 mixed hard drive arrays

[Ricknsa]

Is it possialbe on the new StoreVirtual 3200 to add 4 SSD 400g drives to present to servers as a seperate LUN, from our second array of 8 - 900g SAS. It appears that it will only allow us to create volumes from a combined total from both arrays? How does that affect the proformance of the 12 SSD drives? 

[Stor_Mort · Accepted solution]

Hi Ricksna,

With SSD and 10K SAS drives, the storage is configured as two tiers. Each tier is a pool of all the capacity of each type of storage. Four 400GB SSD drives gives you a pool of something less than 1600 GB in tier 0 and eight 900GB SAS drives gives you something less than 7200GB in tier 1. Here is how it works.

LUNs (volumes) are carved from the total capacity of both stores combined. Because this capacity is virtualized, it is not specifically assigned to any host, storage node or volume, but is assigned to meet the needs of the application "on demand". We call this Adaptive Optimization.

Tier 0 will always be used 100% if there is enough data to fill it. When tier 0 is full, less frequently used 256KB data blocks within an AO volume are automatically moved to tier 1. Blocks which are in tier 1 will move to tier 0 as their access frequency increases above the least frequently used blocks in tier 0. This gives you all the performance benefits of SSD with the large capacities of SAS. If you disable AO on a volume, all those blocks will migrate to tier 1 if tier 0 is full.

[Michal Doležal]

Just small addition - to be completely clear. You cannot set preferred disk tier (affinity function on MSA2040, or special CPG with SSD only on 3PAR), you can just enable Adaptive Optimization (in this case hot blocks will be moved to SSD) on volume, or disable (all datas will be on SAS). There is no way to create just linear drive as on MSA 2040. But good news is that you can have more spindles in logical pool than 16 so you can simply have more IOPs (this is valid mainly for rotational drives). On SSDs you are limited to 25.

You must count also with some disk drive rules so all disk groups must exist in pairs.  As you mention 4 SSDs can be configured only as 2xRAID1 (two Raid groups) = 800GB of usable storage. Best practice is to place SSD as close as possible to controllers.

Reason for that is StoreVirtual platform itself. StoreVirtual 3200 is evolution from StoreVirtual 4000 software.

I installed this array yesterday. Some things are amazing, some of them not so.

[Ricknsa]

Thank You so much for the reply that really helped in understanding the new 3200 configuration

Rick Beare