OK, so as per other thread I have a RAID5 array comprising 4x2TB disks in which I want to replace the disks. Makes sense that I replace with 3TB disks, so that will mean resizing the array.
My options (as I see them) are: 1. Backup all the data on the disks. Replace them all and create a new array. Restore all the data. 2. Replace disks one at a time and let the array recover, leaving blank space at the end of each partition for now. Then resize the array to take advantage of the remaining space. 3. Remove the disks and image them onto the new disks, leaving blank space. Bring the array up on the new disks then resize.
Option 1 is by far the simplest, does anyone see any reason why I should try to be cleverer than this?
(Actually, option 1a comes to mind which is better still: buy the new disks and get them set up in another box, build the empty array, then copy the data across and transfer the disks; much reduced downtime. If the array is ready before the weekend, and I leave the data copying across over the weekend, I should be good to go on Monday..)
I think I've answered my own question but would still appreciate comments.
On Mon, 14 Oct 2013 12:35:31 +0100 Mark Rogers mark@quarella.co.uk allegedly wrote:
Option 1 is by far the simplest, does anyone see any reason why I should try to be cleverer than this?
I don't. I think that you are right to apply the KISS principle. Why invite problems.
(Actually, option 1a comes to mind which is better still: buy the new disks and get them set up in another box, build the empty array, then copy the data across and transfer the disks; much reduced downtime. If the array is ready before the weekend, and I leave the data copying across over the weekend, I should be good to go on Monday..)
I think I've answered my own question but would still appreciate comments.
And that gives me the answer to what I need to do later when I eventually replace the disks in my RAID1 setup. I have a spare box I can use.
Mick ---------------------------------------------------------------------
Mick Morgan gpg fingerprint: FC23 3338 F664 5E66 876B 72C0 0A1F E60B 5BAD D312 http://baldric.net
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On 14 October 2013 13:15, mick mbm@rlogin.net wrote:
And that gives me the answer to what I need to do later when I eventually replace the disks in my RAID1 setup. I have a spare box I can use.
On checking, I find that of the >5TB I have available in my existing array I'm only using <2TB of it anyway, just goes to show it's worth checking these things! So 2x3TB in RAID1 config gives me two spare drive bays to expand in future should I need to and is more cost effective. I've gone with Toshiba drives, whether or not that'll prove to be a good choice I have no idea (I don't use Seagate now that they only put 1yr warranty on them, so it was either Tosh or WD at the price point I was looking at).
I don't think (last time I tried) that there's a way to switch RAID level in-place so expanding that in future will require starting again and copying to and then back from other drives again. If you could create a RAID5 now but with a missing drive that would provide the same mirroring for now and allow it to be easily grown later with 3TB drives but it won't (wouldn't when I tried) create a RAID5 without min 3 drives.
It's possible to frig it using some mdadm trickery but I expect that's not recommended...
Neil
On 14/10/2013 13:29, Mark Rogers wrote:
On 14 October 2013 13:15, mick mbm@rlogin.net wrote:
And that gives me the answer to what I need to do later when I eventually replace the disks in my RAID1 setup. I have a spare box I can use.
On checking, I find that of the >5TB I have available in my existing array I'm only using <2TB of it anyway, just goes to show it's worth checking these things! So 2x3TB in RAID1 config gives me two spare drive bays to expand in future should I need to and is more cost effective. I've gone with Toshiba drives, whether or not that'll prove to be a good choice I have no idea (I don't use Seagate now that they only put 1yr warranty on them, so it was either Tosh or WD at the price point I was looking at).
On 14 October 2013 14:50, Neil Sedger alug@moley.org.uk wrote:
I don't think (last time I tried) that there's a way to switch RAID level in-place so expanding that in future will require starting again and copying to and then back from other drives again.
Sorry, that's me not being clear about my intentions.
I'll create a RAID1 array now with 2 disks. In future I may add a second RAID1 array with two additional disks. OK this won't appear as a single volume (unless I use LVM? Never really played with that, really should), but for my purposes it shouldn't be a major problem - there's plenty of ways I could naturally split the data that I'm storing across two volumes.
Good points though.
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Mark Rogers -
mick -
Neil Sedger