Re: Iseries Disk managment

Traditionally a PC has one physical drive with one head, and one user. 
Now, when that user requests something instead of the disk head seeking 
all over the place for various fragments of that file it will load much 
faster if all segments are in sequence.

Now, when you're dealing with a multiuser system, with multiple drives, 
the file may actually load faster if it can read from multiple heads at 
the same time.  Or, if you are using an application that doesn't read the 
file all at once, and some other user reads a different file and 
repositions the head, then your head needs to move back.  Or, you can get 
lucky and the next chunk is on a different disk that has prepositioned the 
head.

One of the reasons that when you try to defrag a drive associated with an 
IXS, or IXA card it tells you that you can't defrag that drive.  I suspect 
that a PC server that stores their data on a SAN has pretty much the same 
issue.

Rob Berendt