SQL on VNX with FAST

Hi,

I'm looking for some advice and information when hosting a SQL Server on a VNX which is cabale of FAST VP and FAST Cache.

I realise that SQL can really benefit from FAST cache but wanted to know whether the VNX would know automatically to move the highly accessed 64kb chunks into FAST caches if the SQL LUN resides in a FAST VP LUN which has EFD disks.

Or, is it better to place my SQL DB on a SAS based LUN and enable FAST cache on that LUN?

There are no RAID Groups in the array just FAST Pools.

Any advice here is welcome.

Thanks

JB

Responses(1)

S

StephN_AU

51 Posts

0

December 3rd, 2012 22:00

Hi JB

We run many SQL databases on a VNX with a 3 tier FAST VP and FAST Cache. If you read the FAST Cache documentation it states that chunks of data that are already on a EFD disk in a FAST -VP pool do not get promoted up to FAST Cache, only chunks that are sitting on SAS or NL-SAS disk.

The answer of what to do depends on how much EFD disk you have and where you want to place it.

For example one of my busier SQL LUNs shows 3% on EFD, 95% on SAS and 2% on NL-SAS and as I have FAST cache enabled, Im sure a lot of the chunks from the SAS drives are being promoted to the EFD in the cache. Its working for us.

Cheers

Steph

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