I'm currently maintaining a BI server that crunches numbers for reports etc. It is running on a HP ProLiant 360DL G5 32gb ram with a Smart Array p800 connected to a MSA Unit with 750 GB in RAID 1+0 (total 1.5 TB, each disk is 72GBx22 disk). The server it self has 136 GB for OS and 3 logical partitions for Database (293 GB), StageDatabase (292 GB) and DWHDatabase (165 GB). I've been asked to assign each of these partitions to physical disks in the MSA unit, is this possible? Furthermore, I've read that best practice for SQL Servers should be that I change the raid for the OS to Raid 1, and the raid for the data should be raid 1+0?

The primary question here is, how do I map the logical drives to the physical drives?

I'm sorry if it's a stupid question, server setup is quite new to me.


I've been asked to assign each of these partitions to physical disks in the MSA unit, is this possible

Yes, absolutely, via detailed use of the Array Configuration Utility (ACU) or via the F8 ORCA utility - but it doesn't always make sense, in fact doing what you're saying may well worsten your performance.

I'd really strongly suggest you don't do what you've been suggested, any gain seen is likely to be very minor if at all and given the pain of migrating to the proposed configuration it's just not worth the effort.

Out of interest are you sure you actually are having IO performance issues anyway? if so how do you know this?

  • I've read up on it, and technet has a best practice guide to sql servers. it says: Always place log files on RAID 1+0 (or RAID 1) disks. and it also says: Isolate log from data at the physical disk level. So my follow up question is, are you sure it would worsen? Right now, the logs and data is not physically split up, the 22 harddisks is just applied to the same raid 1+0. And the OS is not in a raid. Reference: technet.microsoft.com/en-us/library/cc966534.aspx – psalomonsen May 9 '12 at 11:09
  • I know that document well an if it makes you sleep better then by all means create disk-specific logical disks for data and logs, it won't be 'wrong' as such. In terms of performance if it's all done on one larger logical disk then your data is spread out across more spindles so your random IO will be quicker but don't worry about that, just stick to what MS wrote a decade ago, it's not like anything's changed since then... – Chopper3 May 9 '12 at 11:24

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