What a unique name, July! I hope the following helps your filer situation.
From July at Zerowait on Tue, 28 Mar 2000 15:52:57 EST:
Hello: The filer in question is an inherited box, an F760 with two shelves of 9GB SCSI drives, one shelf of 9GB FC-AL drives all in one RAID and one VOL. The single VOL also contains the root, I think. I've heard that you are supposed to separate SCSI and FC-AL drives into separate RAID groups, but this is how the box came and we can't change it.
Inherited boxes, gotta love 'em! =)
Anyway, my task is to add two shelves of 36GB drives to this unit. I know I need to create a separate RAID group for the 36GB drives. In the man pages I see instructions for adding disks to an existing volume and how to create a volume. I don't see anything that tells me how to create a new RAID group. I must be missing something obvious.
The reason you didn't find any language describing the procedure for creating a new raid group is because you don't have to. =)
When a volume is created, an initial raid group is created, usually with two disks - one for parity and one for data. Once you have added n+2 (where n is the "raidsize") to the volume, it will automatically create a new raid group to house the 2 disks beyond raidsize. Note that you cannot add n+1 disks to a volume because a raid group must have at least two disks.
For example, you create the volume "myvol" with two disks using the command "vol create myvol 2". The default "raidsize" for volumes is 14 disks. If you issue the command "vol add myvol 12", all disks will be added to the first raid group. If you then try "vol add myvol 2" it will automatically create a new raid group with 2 disks. It's that easy!
Things to be aware of:
1) You can not decrease the size of a raid group once it has been filled. Changing the option "raidsize" with the command "vol options <volname> raidsize <# of disks>" only changes the maximum number of disks to be added to the current non-full and future raid groups on the volume.
2) You can not decrease the size of a volume, a corrolary to the above point. Don't commit disks to a volume unless you're sure you don't need them for another volume, or for hot spares.
3) Every raid group requires one parity drive and the max "raidsize" is 28. So if you want more data protection, set "raidsize" lower. If you want to maximize the number of disks used for data over parity and are willing to risk losing the whole filesystem in the event of a double-disk failure, set "raidsize" higher.
Does that answer all your questions?
-- Jeff
-- ---------------------------------------------------------------------------- Jeff Krueger E-Mail: jeff@qualcomm.com NetApp File Server Lead Phone: 858-651-6709 IT Engineering and Support Fax: 858-651-6627 QUALCOMM, Incorporated Web: www.qualcomm.com