raid 6 expansion - options and views please

[VtLgsr245]

Hi guys,

I could do with some expert advice before embarking on expanding my RAID array.

Im using a Areca 1220 8 port RAID card with 5 * 500Gb disks configured in a RAID6 array, 3 data disks = 1.5TB plus 2 redundancy drives.

Option 1
Given I have 3 ports spare, I think I can just an extra 500GB drive and expand the array by 500GB.
Has anyone done this before?

Option2
Im not sure if this is possible, or if so, a good idea, but if so, this might be a good time to do this

Can I replace each 500Gb hard disk with 1Gb units one at a time rebuilding the array each time I swap one. Obviously the array wont see any extra space until all drives are replaced with 1GB units. At which point I should be able to repartition the volume from 1.5TB to 3TB.

I hope thats clear what Im thinking? thanks in advance for any help and have a great 2008!

Ian

 

[Rocco123]

One of the touted features of the 1220 is online capacity expansion and RAID migrations. So yes it is possible. However I do not know if that would work for scenerio #2 that you've described. I have done many OCEs, but on Dell and HP specific controllers. I've never been able to expand a (for example) 3x36GB RAID 5 to a 3x73GB RAID 5 with the extra storage available. It would rebuild and the extra space would never appear in the Windows LDM. Unless Areca has done something different, it wouldn't work for this controller either.

So yes, you can add disks, and you can do so with the volume online. Performance will take a hit, and it's probably a good idea not to have too much I/O going to the array during the expansion.

You could also do away with RAID 6 and migrate the array to RAID 5 (another feature of the card), and expand with more disks. RAID 6 is probably overkill and creates a little more overhead for writes. Not steering you away from what you want, just my opinion.