That is really a good description of what to do, but ... What about the situation of building a new raid on the same volume. Can I set the raid size to 13, build another raid with the 36 GB drives onto the same volume, change the raid size to 14, add one more 36 GB drive to that raid set, then add 13 more 36 GB drives to another raid set on the same volume?
I've got four shelves of 18 GB drives in two raid sets of 14 and 13 with one spare. I want to add two raid sets of 14 and 13 of the 36 GB drives with one spare for that group. ... All in the same volume. also, the four new shelves are the new ones that can handle the 36 GB drives. The result is a spare for each of the 18 and 36 drives and full shelves.
With spares and parity; I think this keeps me under the 1.4 terabyte limit on the filesystem.
At 2:57 PM -0800 3/28/00, Jeff Krueger wrote:
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:
- 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.
- 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.
- Every raid group requires one parity drive and the max "raidsize" is
- 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
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