Additional Disks

[joe.beaton]

Hi,

We have a 7200 with 48 x 300GB 15K disks. All disks are in the same CPG.

We want to expand some more. I was looking at getting some 900GB 10K disks and putting them in the same CPG as the 300GB disks.

Is there any reason not to do this? Is there any reason not to mix different speed/size FC disks in the same CPG?

Thanks in advance.

Joe

[hdtvguy]

Hi,

We have a 7200 with 48 x 300GB 15K disks. All disks are in the same CPG.

We want to expand some more. I was looking at getting some 900GB 10K disks and putting them in the same CPG as the 300GB disks.

Is there any reason not to do this? Is there any reason not to mix different speed/size FC disks in the same CPG?

Thanks in advance.

Joe

Not a good idea. The way the 3par distributes chunklets it will try to keep them evenly distributed. By have some drives with 3x capacity you will fill up your 300GB drives and then wind up with uneven distribution of chunklets. We had a similar situation and put the 900GB drives in their own CPG. IT has created some balancing issues for us anyway as I have 50K IOPS in 300GB drives and 23K IOPS in 900GB drives, so I wind up with some awkward AO configs that do nto work as well as I would like.