How much SSD Tier for a hybrid one?

[DukeR1337]

Hi all

Is there a general advice or white paper about how much SSD capacity (tier) we should install in a pool for tiering? 20%?

Cheers and thanks

[kelleg]

See the Unity Best Practices White Paper

h15093-Dell_EMC_Unity-Best_Practices_Guide.pdf

glen

[DukeR1337]

Well the statement looks like "put us much as possible" which is not really a quiantifier any recommendation based on your experience?

[kelleg]

Page 13:

Dell EMC recommends provisioning a Flash tier in hybrid pools. The Flash tier helps enable pool performance efficiencies, and improves response times when using Snapshots and/or Replication. The minimum recommended Flash capacity is at least 5% of the pool capacity.

The minimum should be at least one, 4+1 R5 - more is the size of the Pool is very large, then use the 5% recommendation.

Also, pay particular attention to the section on page 11 "GENERAL RECOMMENDATIONS".

glen

[Rainer_EMC]

I would see that as a minimum - esp. for thin provisioning since this also includes the metadata which is preferably put on flash

So if you want 5% user data on flash you need more than that

[DukeR1337]

Hi both,

Thanks very much I think I can work with this! I appreciate your patience and engagement.

Cheers

[kelleg]

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glen