i have a disk shelve of 24 x600GB disks.i want to create a aggregate now what should i do should i use all the disk in one raid group or should i have multiple raid groups in an aggregate .Can any one suggest me the best practice to do it .
It would be helpful to have a bit more information. Also, did you mean 8.1 7-mode Ontap? AFAIK, there is no version 8.1.7 yet. Assuming 64-bit aggregate and raid-dp, I would create one raid group of 22 disks (save 2 disks for spares).
With SAS drives you can put up to 28 disks in a raid group or as little as 3.
So just create a new aggregate and put 23 disks in the aggregate and leave one as a spare.
The raid groups will automatically be created for you, however you can adjust the amount of disks before a new raid group is created in the aggregate.
I'm less conservative when it comes to this and take full advantage of 64bit aggregates, so I agree with what you're trying to do.
Here are some Pros and Cons,
Pros: Better capacity, ability to create bigger volumes in return for bigger dedupe savings, and more iops.
Cons: More exposure to a double disk failure and longer rebuilds on a disk failure.
You could go a little deeper than that, but for me, these are the biggest factors. If you haven't already, grab OnCommand System Manager 2.0.2 from the downloads section on support.netapp,com and do it up!