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RAID 6 Expansion

 
EcosseSMB
Occasional Visitor

RAID 6 Expansion

Can you assist - not a technical background but can learn! - our ML370 G5 has a P400 controller (with battery/512) and is configured Raid 6 ADG with 4 disks.  They were originally all 72gb, but due to failures 2 are now 146gb!  Array is partitioned C (system) 50gb which has 12.5gb free, E (Exchange server) 43gb which has 27gb free, and F Data 43gb which has 5gb free. I want to expand the data partition.  I have bought a new matching 146gb disk & it is hot swap so easy to configure.  However, although I can see that I can add it to teh array, creating a 5 disk array & gaining I think just 72gb?, then can combine the spare space to the F partition using Diskpart.exe?, it did occur to me that if I swapped one of the old 72gb out for the new disk  & then also bought another 146gb disk to swap the final 72gb out, I would then have a 4 disk array all of 146gb!, and I think that with each swap out it will rebuild on the new disk in the same way as if you have a disk failure? Then the small disks will be used as spare non-critical space on a new array.

Question though is, (a) which is the better option?, and (b) if I swap out the disks, it rebuilds, but will teh "spare" space then become available to extend the array & which partitions can it be used on? (I think diskpart.exe just adds to the end of the partitions?  OS is SBS 2003 R2.

Thanks!

1 REPLY
LouisH
Valued Contributor

Re: RAID 6 Expansion

Ecosse,

 

Easiest thing to do is swap out both remaining 72GB disk with 146 GB disks. This will double your available space in your RAID6 array. If you use (M$) Diskpart, you will not be able to extend the primary partition. All available space will show up as available after the "F" partition under the OS once the array is expanded/extended within the SA controller.

 

You can use something like "partition magic" to add space to any partitions you choose. You can also use Linux utilities to do the same.

 

We have done both with success. As always, get a good backup of system state and data before you start mucking around with the partitions.

 

As a rule, we would get a backup before swapping out smaller disks for larger ones, and then again after the SA controller expanded and extended the logical volume.

 

Swapping the disks could take a day per disk, before the expansion and extention is done. Only swap one disk at a time.

 

 Using a 72GB as a spare would not work. I don't think the SA controller would let you as disks are different sizes.

 

better to use the smaller disks in a seperate logical drive.

 

Louis