sql-lover (8/23/2013)
I am sorry to disagree... but for a SAN with actual mdf and ldf files there, I see no reason to defrag, specially if we are talking about TBs of data. I know NTFS creates fragmentation and a SAN can be fragmented, that's true, I just believe there are other ways to fix or improve that, for example, picking the right RAID or improving the actual disk's pool or LUN design.This is a very controversial topic, but most modern SANs use a different technology and the actual file is all over the place using very complex algorithms, and let's not even talk about automated tier systems SANs. So the benefit of running a defrag is minimum.
Having said that, I am aware that most SAN systems provide such defrag tools. So I would rely on my SAN admin or a SAN expert and ask him if he really recommends such task and if I will get a benefit or not.
Well - we can agree to disagree. With that said, the SAN has no idea about the files or even the file system. On the SAN you create a volume and mount that volume on a server. The volume could be mounted to a Unix, VMS, Windows, Linux - or other OS system.
The file system can be NTFS, FAT, FAT32, NSF or other file system.
The SAN has no idea what happens on the OS or with those files. Don't trust me - open perfmon and check out your split I/O's. If you have a file with a lot of file fragments you will see a lot of split I/O's occurring which can only mean you are experiencing a performance hit.
Jeffrey Williams
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