July 1, 2010 at 3:28 pm
Our database server is running on RAID5 and when it was setup it was not configured properly.
We have a 31.5Kb starting offset and our bytes per cluster is at 4Kb. We are having pretty serious I/O Performance issues and I'd like to resolve them by getting the disk setup properly.
I'd like to hear from anyone who has done this on either a production or a test machine. Specifically hyow you transferred the data and moved it back over once the partitioning was complete as well as any hitches along the way.
Thanks!
Even as a mother protects with her life
Her child, her only child,
So with a boundless heart
Should one cherish all living beings;
July 1, 2010 at 4:03 pm
I haven't done it, but I have a friend that shut down SQL, copied everything off, repartitioned the disks, copied back, restart SQL (or detach/attach the dbs)
July 1, 2010 at 8:08 pm
So the hard part of this is simply finding a hard drive big enough to store what's on there now. It sounds like it's basically reformatting the hard drive..only scarier.
Even as a mother protects with her life
Her child, her only child,
So with a boundless heart
Should one cherish all living beings;
July 2, 2010 at 8:47 am
That's what you're doing, just starting the format in a particular place.
Have you read this: http://sqlcat.com/whitepapers/archive/2009/05/11/disk-partition-alignment-best-practices-for-sql-server.aspx
July 2, 2010 at 9:18 am
I actually have that paper open on my desktop. I came across this powerpoint presentation that also contains excellent supplementary information: http://cid-2c2c54bdef4e3eb4.office.live.com/view.aspx/DiskPartitionAlignment/Disk%20Partition%20Alignment%20for%20SQL%20Server%20--%20Jimmy%20May%20--%20v.20090201.ppt
Also for some hard data resulting from tests this short article and the followup blog posts are worth a read: http://sqlblog.com/blogs/linchi_shea/archive/2007/02/01/performance-impact-of-disk-misalignment.aspx is worth
Our IT guy installed the disk viewer yesterday but I need to reboot the db server before it will see the controller and be able to get the Stripe Unit Size. If the article you mention is correct it may be the same as Bytes Per Cluster seen with the fsutil command. I actually have enough information on hand to prove that the disks are not optimized since out Partition offset is 31.5Kb but having the SUS will be good.
Does anyone know how to determine the optimal Starting Partition Offsets? Also does the bus size or speed play any part in setting these? If SS2008 always writes in 64Kb bursts then does it make any sense (as in savings) to create the offset as a multiple of 64Kb? It's times like this I wish I had an A+ cert!
Even as a mother protects with her life
Her child, her only child,
So with a boundless heart
Should one cherish all living beings;
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