Best steps to get back up and running after a 2-drive failure

[BeeKay]

Hi guys, hoping to get some advice.

 

Had an array working fine for ages, 6 data + 1 parity +1 cache… however I’ve suffered a 2-drive failure and now need to get back up and running.

 

Long story short… I managed to copy all the valuable data from the remaining drives (just to be safe) through mounting them as read-only and copying files to a USB hard drive. The valuable data was pictures, documents, backups etc.

 

There is also a heap of media on the drives, which I don’t have room to pull off to external drives but would love to keep if possible. 

 

My question is… can I reconfigure the array to disregard the lost drives and their data, whilst keeping the remaining media on the healthy disks available again in the array?

 

Have a feeling this might be basic unraid functionality but would love some assurance.

 

Thanks heaps.

[trurl]

How did the drives fail? Are you sure the disks themselves failed and it wasn't some other issue, controller, cables, etc?

 

You can reassign disks however you want with Tools - New Config. It won't change anything except it optionally and by default rebuilds parity. In your case you need to let it rebuild parity. Be sure you don't assign a data disk to the parity slot.

[BeeKay]

8 hours ago, trurl said:

How did the drives fail? Are you sure the disks themselves failed and it wasn't some other issue, controller, cables, etc?

 

You can reassign disks however you want with Tools - New Config. It won't change anything except it optionally and by default rebuilds parity. In your case you need to let it rebuild parity. Be sure you don't assign a data disk to the parity slot.

Thanks for the reply.

 

Yes, I'm sure the disks failed. There's a backstory, which I thought to lay out originally but then felt it may not be relevant, but yours is a fair question. Basically, I've been running a bit of a frankenstein setup involving my HP microserver gen8, with an LSI 8i HBA, running sff8087 to 4x sata through the back of the HP to an externally positioned 4xhdd cage (one of the 3x5.25 bay caddys). The hdd cage was connected to a separate PSU with a jumper wire to enable it to power up without a motherboard connection.... yes.... I know, dirty.... my own skin crawls in the retelling... anyway while I was troubleshooting the drive not appearing in unraid, I was moving the drives between bays to test the SATA connection on the back of the caddy, these seemed fine... the problem/my mistake came when I started playing with the jumper wire on the PSU.... the PSU is a Corsair SF600 which is 'clever' in that it doesn't spin the fan until needed. The spinning fan could be considered a simple visual indicator that the PSU is on and doing its thing, but not with a PSU that doesn't run the fan by default. So I was effectively messing with the jumper while the PSU was on and providing power to the drives.

 

So I fried the PCBs on the drives. Confirmed by the hdd technician at a local data recovery provider... they managed to swap the PCBs on all 3, replace the BIOS, and two came back. The third is believed to have suffered damage to the heads as well. I received the two repaired drives back, added them back to the original caddy and PSU arrangement, they appear in unraid. I then manually mounted all the disks and laboriously copied the critical data off. Managed to get all the pics docs and backups off, don't have the spare drives to do same for the media on there...

 

RE an odd behaviour from the hdd cage and PSU arrangement, before all this... unraid would be happily running the array for months, and when I would reboot (for a non-issue related reason) it would often restart with Disk 4 as missing... I would reach behind the hdd cage, give the SATA connectors a press and the drive would come back as visible in unraid (all done without powering down/up). I'd start the array and go about my day. So I took from this that the sata cable/connector on the back of the hdd cage was not 'great'.

 

The whole issue that set me off playing with the cables/PSU was due to Disk 4 disappearing like above, but not coming back from the usual cable pressing on the back. 

 

Long story long, I feel...

 

Q1 - when you say Toole - New Config won't change anything escept it rebuilds parity... does this mean that it will create a new array config, with all the available drives, presenting all their existing data, with all the existing shares/etc? Then, all I would effectively notice is that some folders/files are not visible in the shares that were there previously?

 

Q2 - I have bought 2 new HDDs to add to the array. One is a 10tb to use as a second parity drive (existing is also a 10tb), and the other is a 10tb to add as a new data drive for the arry... should I run the Tools - New Config step before adding second parity, and likewise with the new data drive? e.g. should I follow - do the new config, it completes, add 2nd parity, it completes, preclear then add new data drive, it completes... ? 

 

Sorry for the essay. Thanks for your help.

[BeeKay]

PS - I wasn't sure the Tools - New Config step was what I was after, but some quick searching now it seems to be answering my follow-up Qs above. Thanks again.

[trurl]

5 minutes ago, BeeKay said:

it will create a new array config, with all the available drives, presenting all their existing data, with all the existing shares/etc?

yes. All files on the existing disks will be there, and all shares will be there since they are just the top level folders.

 

A2

You don't mention the size of your existing parity disk, but of course no data disk can be larger than any parity disk, so if each parity isn't at least 10TB then you can't add a 10TB data disk.

 

You can actually do all of it at the same time. Parity will just be built based on the assigned disks regardless of their contents. Doesn't matter if they are clear or have random bits or actual files. And formatting (writing the empty filesystem to the new disk) in the array will update parity at the same time (since it is a write operation), so parity will still be good.

 

As I already mentioned, be sure you don't accidentally assign a data disk to any parity slot, or it will be overwritten with parity. And before formatting the new disk, make sure all the existing disks are showing their filesystem and size. In other words, make sure they aren't unmountable, since format applies to all unmountable data disks. If you have that problem come back for further advice on repairing unmountable filesystems.

[BeeKay]

22 minutes ago, trurl said:

yes. All files on the existing disks will be there, and all shares will be there since they are just the top level folders.

 

A2

You don't mention the size of your existing parity disk, but of course no data disk can be larger than any parity disk, so if each parity isn't at least 10TB then you can't add a 10TB data disk.

Thanks heaps.

 

RE the parity drive, I mentioned the existing parity as also a 10tb, but yep I understand what you're saying that the parity drives need to be as big as/bigger than the largest data drive. Cheers.

 

Sounds like I can just add the drives I want to end up with in the new config step, and I heed your warning around existing disks showing their fs and size and not showing as unmountable...