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2 Bronze

Best Practice - # of Disks in a FAST VP Pool

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Hello -

We have a CX4-240 running FLARE 30.  Our goal is to collapse existing traditional RG/LUNs and migrate to FAST VP Pool.  The array has the following types of drives:  450 GB FC, 600GB FC, 600GB FC, 1TB SATAII.

FAST Cache is enabled on a couple of 100GB SSDs.

We currently have an existing pool with 8x 1TB drives, and 8x 600GB FC drives.  We'd like to expand the pool by adding the rest of the drives in the array after migrating/collapsing the traditional RGs/LUNs.

What is the best practice when it comes to FAST VP pools?  According the EMC documentation, a pool can include all disks in the array.  This is the path we are leaning towards; 1 pool with all disks in the array.  Is this something you folks see out there?  Multiple pools?

Also, we will be enabling Snapview in the array as we will be configuring it for Commvault's Snapprotect.  Do you see any issues with creating Reserved LUNs off of FAST VP Pool/s?

For the Vault drives, I am thinking of leaving those on traditional RG.

Thanks for you input in advance.

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5 Rhenium

Re: Best Practice - # of Disks in a FAST VP Pool

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First off, is your requirement ease of managing capacity or performance? If performance then stay with raid groups, there is always more overhead with Pools.

For best performance Reserve LUNs should stay in traditional raid groups and do not enable FAST cache for those.

Create Pools for different types of usage. Just like with raid groups, if you want the best performance you should not put a lot of different types of applications in the same pool. If you have heavy random Write apps, then create a R10 Pool. If you have Database apps, then you should probably have two types of pools - R10 for the LOGs and Temp (no FAST cache ) and R5 for the database (FAST cache good for this).

There's a lot of good information in the FAST VP White Paper (two attached). See page 32 in the Oct 2011 White page for Best Practice recommendations.

glen

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5 Rhenium

Re: Best Practice - # of Disks in a FAST VP Pool

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First off, is your requirement ease of managing capacity or performance? If performance then stay with raid groups, there is always more overhead with Pools.

For best performance Reserve LUNs should stay in traditional raid groups and do not enable FAST cache for those.

Create Pools for different types of usage. Just like with raid groups, if you want the best performance you should not put a lot of different types of applications in the same pool. If you have heavy random Write apps, then create a R10 Pool. If you have Database apps, then you should probably have two types of pools - R10 for the LOGs and Temp (no FAST cache ) and R5 for the database (FAST cache good for this).

There's a lot of good information in the FAST VP White Paper (two attached). See page 32 in the Oct 2011 White page for Best Practice recommendations.

glen

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2 Bronze

Re: Best Practice - # of Disks in a FAST VP Pool

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Hello vlr2714,

When creating or expanding pools, the recommended pools sizes are multiples of five for RAID 5 and multiples of eight for RAID 6.

When using different capacity drives to create a pool, it is best to do this in stages. For example, if you have ten 600 GB drives and five 300 GB drives, first create the pool selecting only the ten 600 GB drives, and then expand the pool by adding the other five 300 GB drives.

General speaking, having multiple pools will give you more flexibility, as you can create a pool with RAID-5 configuration for performance LUNs and other pool with RAID-6 configuration for capacity LUNs, it depends on your needs/preferences.

For Replication, You cannot use pool LUNs as private LUNs (Clones Private LUN, MirrorView Write Intent Log LUN) for SnapView and MirrorView replication software.

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6 Indium

Re: Best Practice - # of Disks in a FAST VP Pool

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Consider not putting different FC disks in the same pool! If you have a pool consisting of 300GB 15k disks and you add 600GB 15k later or even 900GB 10k later, then you end up with a pool which sees all those disks as the same tier, since they’re all FC!!! The FAST feature that normally would equalize based on performance will nog leave large parts of the bigger disk unused since they perform equally good as the disks that are equally filled, leaving empty space on the bigger disks. If you want to use disks of different capacity, consider creating different pools.

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7 Thorium

Re: Best Practice - # of Disks in a FAST VP Pool

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RRR wrote:

The FAST feature that normally would equalize based on performance will nog leave large parts of the bigger disk unused since they perform equally good as the disks that are equally filled, leaving empty space on the bigger disks.

is this documented somewhere ?

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6 Indium

Re: Best Practice - # of Disks in a FAST VP Pool

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I know I saw it somewhere, but it is discussed here before: https://community.emc.com/message/657548#657548. When I see it in the documentation, I'll let you know.

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7 Thorium

Re: Best Practice - # of Disks in a FAST VP Pool

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i though we could not mix raid types in a pool on Clariion (flare 30), can we ?

Shawky wrote:

Hello vlr2714,

When creating or expanding pools, the recommended pools sizes are multiples of five for RAID 5 and multiples of eight for RAID 6.

When using different capacity drives to create a pool, it is best to do this in stages. For example, if you have ten 600 GB drives and five 300 GB drives, first create the pool selecting only the ten 600 GB drives, and then expand the pool by adding the other five 300 GB drives.

General speaking, having multiple pools will give you more flexibility, as you can create a pool with RAID-5 configuration for performance LUNs and other pool with RAID-6 configuration for capacity LUNs, it depends on your needs/preferences.

For Replication, You cannot use pool LUNs as private LUNs (Clones Private LUN, MirrorView Write Intent Log LUN) for SnapView and MirrorView replication software.

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3 Zinc

Re: Best Practice - # of Disks in a FAST VP Pool

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Correct, you can only mix in R32 which is not available for the CLARiiON, only the VNX.

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2 Bronze

Re: Best Practice - # of Disks in a FAST VP Pool

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Hi dynamox,

That is correct mixed Pools are only available in R 32 so, only for VNX.

I mentioned 2 configurations of 2 pools, and did not mentioned that it is mixed in one pool

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7 Thorium

Re: Best Practice - # of Disks in a FAST VP Pool

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Oops..read it as mixing r5 and r6 in one pool .