[cdelgadop]

Hi, i know this is an pSeries forum but given that an UNIX admin always has to do with many enviroments.

My customer has an IBM SAN Volume Controller with some storage
boxes connected, let's say an IBM DS8100 and a new DS8300. We
have defined some volumes in the DS8300 of 1.6 TB and created
some Mdiskgroups in the SVC with one of such big volumes as one
whole mdisk.

My question: what's the best practice for creating such volumes
?? is it better to create small volumes and small mdisk and
assign them to many mdiskgroups or just create big volumes as
the sample below ??

Another question: What's the meaning of the extend size in the
mdisk ?? we have a extend of 16mb. Is this the best size from
performance point of view ??.

Thanks in advanced

[Administrator]

The best way to this, especially if the storage device is new is to use the largest LUNs and fewest managed disk groups are possible. Create your virtual disks across all of the managed disks in the managed disk group.

This spreads the IO of the virtual disks across the greatest number of physical spindles, reducing the change of I/O contention and host disks.