Dynamic Disk
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Greetings all,
Looks like my month for noob questions. I seem to remember in an administration course a while back when the instructor advised to never use dynamic disks for SQL Server installations. We just received 2 new servers that will be Windows 2000/SQL Server 2000 and my network admin built the OS partition as NTFS but built the other 2 raid sets (all disk sets are hardware level raid 1) as dynamic disks which set off an alarm somewhere back in the dark corners of my brain. Is this now "old-think" or should I have him rebuild them as NTFS? My cheif concerns with these servers are fault tolerance, stability and performance. With new servers (each are dual 3 gig processors, 4 gig RAM) am I splitting hairs about any processor overhead using dynamic disk? Do I really gain anything by using dynamic disks? I'd rather just have each RAID set as one large NTFS partition as that's what I'm used to working with but am open. Your thoughts are appreciated.
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Dynamic disks shouldn't really be used with SQL, however they are less of a concern in a normal scenario, the biggest problem comes if you try to use dynamic disks in a cluster as the ownership gets all screwed up.
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There are some problems with dynamic disks that can hit any machine, not just SQL Server ones. The problems appear to stem from the (Windows) database that holds details about all dynamic disks...
1) If you need to unmount & mount disks (e.g. as part of a failover strategy), then the dd database can get upset. Often this can only be cleared by rebooting the server.
2) If you are using a SAN and expand a volume described by a dd definition by attaching more LUNs to it, the dd database can get upset.
3) If the guid of any disk known to the server changes without the server issueing the commands to make the change (SAN control volumes are prone to this), the dd database can get upset.
None of the above problems seem to occur if you use basic disks.
On the other hand, we have run a 200GB data warehouse on a server using direct attached storage defined as dynamic disks without any problems. Dyamic disks seem to be stable if they are just left in peace.
Original author: https://github.com/SQL-FineBuild/Common/wiki/ 1-click install and best practice configuration of SQL Server 2019, 2017 2016, 2014, 2012, 2008 R2, 2008 and 2005.
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