I've recently replaced a 3TB disk with a 12TB disk in the array, which went fine it was rebuilt successfully. However, there are other disks that are failing and I'd like to remove them. I've removed the content on the drives I want to remove just using rsync and removing the source.  I've read the procedure on the wiki regarding removing drives and using the "new config" tool. My understanding is the files on all the disks (aside from the disks being removed) will be fine, I don't need to copy them off (which is good I don't have the capacity to do a full backup). 

 

The question I have is, what about the cache? I have a lot of stuff on the cache exclusively, for example appdata, domains, system. Is all that going to be fine?

 

I'm using 6.7 and I can see there is an option for "persevere current assignments" which presumably I want to enable for 'all' right?

 

When I rebuild the array do I need to put each disk back where it was? Specifically I have 9 disks plus parity at the moment, disk8 is the one I want to remove, so do I leave disk 8 blank in the new config or can I move 9 to 8? Not that it matters, it's ok to have a gap I guess, I'm just interested in the structure.

When you use the New Config tool then data is left intact, but (except in very special cases) parity needs to be rebuilt.   UnRaid will recognise that the disks have previously been partitioned and formatted by Unraid so it leaves their data intact when you next start the array after doing a New Config.

 

The easiest thing is to use the option in New Config to preserve all current assignments as it reduces the chance of you mistyping a serial number..   When you return to the Main tab all disks should have a blue icon to indicate Unraid has not yet ‘committed’ their serial numbers.  At this point you can make any changes you want, and this includes removing unwanted array disks or re-ordering existing ones.    When you then start the array Unraid will need to rebuild parity based on the remains data disks.   It as this point that Unraid effectively ‘commits’ the serial numbers of the disks it is using going forwards.    Once the array starts you should immediately see all your data intact although it will obviously not be in a ‘protected’ state until parity has finished rebuilding.

 

if at any stage there is an unexpected option to format any data drive do NOT do this   Formatting will erase the contents of a drive and update parity accordingly.  Instead stop and ask for advice.

4 hours ago, itimpi said:

When you use the New Config tool then data is left intact, but (except in very special cases) parity needs to be rebuilt.   UnRaid will recognise that the disks have previously been partitioned and formatted by Unraid so it leaves their data intact when you next start the array after doing a New Config.

 

The easiest thing is to use the option in New Config to preserve all current assignments as it reduces the chance of you mistyping a serial number..   When you return to the Main tab all disks should have a blue icon to indicate Unraid has not yet ‘committed’ their serial numbers.  At this point you can make any changes you want, and this includes removing unwanted array disks or re-ordering existing ones.    When you then start the array Unraid will need to rebuild parity based on the remains data disks.   It as this point that Unraid effectively ‘commits’ the serial numbers of the disks it is using going forwards.    Once the array starts you should immediately see all your data intact although it will obviously not be in a ‘protected’ state until parity has finished rebuilding.

 

if at any stage there is an unexpected option to format any data drive do NOT do this   Formatting will erase the contents of a drive and update parity accordingly.  Instead stop and ask for advice.

Hi @itimpi, thanks for the detailed answer, this helps my understanding a lot. I just wanted to make sure data on the cache will be treated in the same way as the data on the array disks? i.e. for my shares that I have exclusively on the cache like appdata and domains, will Unraid rebuild those if I preserve all drive assignments?

The cache will be fine as long as you leave the assignments alone.

 

Just remember do not FORMAT anything as that is the point at which data can be lost

Edited May 28, 20197 yr by itimpi

16 minutes ago, itimpi said:

The cache will be fine as long as you leave the assignments alone.

 

Just remember do not FORMAT anything as that is the point at which data can be lost

Roger that! Will do. 

Appears to have worked just fine for both the cache and the array disks, content still all there. Thanks @itimpi, I just wanted to check it was safe before I proceeded.