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We have a system in the field running a server application which is suffering with major performance issues.

The system in question has 2 onboard 300gb sas drives in RAID 0+1 from which it boots Windows Server 2003, and a 6tb buffalo terastation NAS unit (RAID 5) to which the server app does all of its reading and writing.

I believe the terastation is the source of all our woes. Whilst under load, reads and writes tick by at something of the order of 1meg/sec, though the network in question is hardly utilised.

The terastation contains various data, but crucially hosts a full instance worth of SQL Server .mdf and .ldf files (master etc - the whole shooting match)

I wish to stop all the services on the server, then take everything on the terastation and essentially clone it to some alternative onboard storage, so as to eliminate the terastation from the equation as far as poor performance is concerned. ie the terastation is currently drive D: - I want to copy everything off and then have the duplicate assume the drive letter so that as far as the software is aware, nothing is different.

This is tricky because of the mdf and ldf files - everything else will work with a straight up file copy. Can anyone suggest a means to achieve what I am describing? Many thanks!

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The Terastation is definitely slowing you down, probably by a significant amount but your description of the setup makes it a bit hard to say by how much. You can't have RAID 5 on a two drive pack - it's probably RAID 1.

The simplest approach, if it's possible with your hardware, is to add another two internal drives in a RAID 1 pack.

  1. Format and mount them as whatever drive Windows wants to make them.
  2. Stop all SQL Services.
  3. Copy the folder structure that contains the database from the NAS drive to this new drive, and anything else you want (or need) to keep on drive "D:", ignore the letter this drive is using for now.
  4. Unmount the NAS drive - you need to free up the drive letter.
  5. Use the Windows Disk Manager to assign the new drive that now contains a copy of the SQL files as drive D:.
  6. Remount the NAS share if you need to as a different drive letter.
  7. Restart all the SQL services.
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You may need to do some serious hacking depending on how you've got the NAS setup. There's a reason that SQL Server doesn't officially support using a NAS for its storage. – mrdenny Dec 30 '10 at 23:55
Indeed that is correct - I beg your pardon; the boot drive is raid 0+1. On the basis that merely stopping SQL server services will allow me to copy the mdf and ldf files, we shall proceed apace with this plan, and I shall report back! – Adrian Hand Dec 31 '10 at 0:42
@mrdenny - assuming it's installed as a NAS and its a mapped network drive the above instructions should work. If it's connected using iSCSI then the only complication will be that the assigned drive letter for the iSCSI volume would have to be changed using Disk Manager at step 4, although disconnecting it should still suffice. – Helvick Dec 31 '10 at 1:24
Based on the title of the question saying that it is a NAS drive, I'm assuming that it is installed as a NAS. – mrdenny Jan 2 '11 at 11:09

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