INFO/SUGGESTIONS Please : SQL performance (fragmented disk)

I'm a developer at my company, but I've worked with hardware quite abit at my last job. I'm finding it hard to talk to one of our system admins here.

I'm running into what looks like disk issues on our SQL Server, I know the DB files all reside on a large SCSI Raid, the only files on the RAID are the DB files, no OS or program files.

Also the disks have never been defragmented, he wants to say :

1. SCSI and RAID eliminate the impact of fragmentation.
2. SQL doesn't get impacted by physical fragmentation.

I know both to be false statements but don't want to start an argument, nor go over his head.

I would like to "find" some reputable articles dealing with disk fragmentation and SQL(database) performance..

If anyone has a good site that displays good information I would greatly appreciate it.

OR

If anyone has some personal experience with issues like this, please share them..

You may want to read the following white paper: 'Microsoft SQL Server 2000 Index Defragmentation Best Practices' (http://www.microsoft.com/technet/prodtechnol/sql/2000/maintain/ss2kidbp.mspx), which may give you more idea about fragmentation.

Thanks

Stephen