NTFS Fragmentation may be more harmful than you think
I’ve posted previously about the adverse affect of ntfs fragmentation and I’ve also mentioned that it is sometimes suggested that fragmentation is not a concern on a SAN.
I’ve yet to finish testing this on a SAN, after all you don’t often get a free play with a SAN for this type of testing, but I did find that extreme fragmentation of the mdf files on a SAN did degrade performance .. sadly I didn’t have the time or resource available to complete my tests.
However, I see that CSS SQL Server Engineers ( Microsoft Customer Service and Support (CSS) SQL Support ) have put out quite an extensive post which covers the subject of ntfs fragmentation and SQL Server.
What is interesting is that a KB which only lists vista has been marked as applying to W2K3 and Windows 2008 http://support.microsoft.com/kb/967351
I suggest having a good read of this if you don’t normally pick up posts from this blog.