Monday, December 3, 2007

Adding Dynamic Disk from Storage Foundations (VSFW) and Microsoft Cluster Service (MSCS) in Windows 2003 R2 x64

I recently had to fight with getting some LUNS configured and presented as dynamic disks to a SQL 2005 x64 (SP 2 Build 3159) cluster running on Windows 2004 x64 R2 SP2. It wasn't as easy as I thought it would be.
The first problem is that the quorum disk can NOT be a dynamic disk. So if your storage guys are presenting 100GB LUNS get ready to waste a lot of expensive SAN disk. If you want to run in a config that's "not supported by Microsoft" you can partition the LUN that you'll use for the quorum such that the quorum parition gets only a small percentage of the disk, and then you can use the rest for something else like logs, backups, SQL binaries, etc.

Here's the steps to getting the dynamic disks in the cluster:
1. Configure your dynamic disk group(s) any way that suits your needs but be sure to create them as a cluster disk group or you're going to fail the next part.
2. Add a "Volume Manager Dynamic Disk" resource top your SQL cluster group.
-If you created the disk groups as cluster resources then you should see them in a drop down menu at the end of the configuration for this resource. If you don't or don't even see the Volume Manager resource then you need to do this fix.
NOTE: When you add the resource the disks will go offline and then back online. Be sure you're not doing anything with them when you do this!

You now have a SQL cluster resource with dynamic disks that's ready to have SQL installed, or if it's already installed then you can migrate your db files as needed.

Dynamic disks are the way to go as you can easily grow volumes, extend stripes, add mirrors, etc. I never use basic disks when I connect a SQL server to a SAN.

Random note:
I like to setup at least one LUN for logs (ldf) and at least one more for data files (mdf)... If the server is going to be under enough load I'll make sure tempdb is on it's own LUNs as well. (System Center Operations Manager is an example of that config).

See this post for a potential resolution with VCS disks not showing up.

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