BTRFS Raid0 - cache drives missing

[navinrs]

Hi,

 

I am running a unraid with both Hard Disks on the main pool and nvme drives on the cache pool. 

 

The Hard Disks are running just fine with no issues, it is a mix of 12 TB Seagate Enterprise Drives and 8TB Drives.

 

Cache Pool is based on four Crucial Nvme P1 Drives on Raid0 using btrfs. This was running well since the past few weeks. Recently due to a sudden power outage, I believe two out of four drives went missing. 

 

When I checked the dashboard, the two drives were not visible out of four. Specifically - nvme1n1 and nvme2n1 . I understand it was a cache drive, but we did have some data which is not available elsewhere on this, bad mistake!

 

Upon rebooting - the drives are showing up but they are unassigned. When I check the drives to assign them as cache drives - there's a red message which shows all data will be overwritten. Which I don't want to happen.

 

Tried mounting the drives using Unassigned Drives plugin, and I was able to see the directories, partitions. 

 

Is there any way to recollect the data? Please help, newbie here! Thanks!

[trurl]

Go to Tools - Diagnostics and attach the complete diagnostics zip file to your NEXT post.

 

Don't do anything without further advice.

[JorgeB]

5 hours ago, navinrs said:

When I check the drives to assign them as cache drives - there's a red message which shows all data will be overwritten. Which I don't want to happen.

Stop the array, if Docker/VM services are using the cache pool disable them, unassign all cache devices, start array to make Unraid "forget" current cache config, stop array, reassign all cache devices, re-enable Docker/VMs if needed, start array.

 

Alternatively you can also do a new config and reassign all devices, then check parity is already valid before starting the array.

[navinrs]

Thanks for the quick revert, trurl & johhnie!

 

I am attaching the diagnostics file that I downloaded a couple hours back. At this moment, I was able to mount the cache drives and copy data from that to a different drive. 

 

 

tower-diagnostics-20191117-0657.zip

[navinrs]

I had one more question if you guys can guide me through the way, it'd be amazing. 

 

I have a share setup to use Cache Drives only, and I wanted to have an automated backup of that share, maybe hourly backup ?

 

This share is mainly used for video editing, and contains large project files. Would prefer a backup system that updates the files automatically in the same unraid box, or a different NAS. Hope this is easy to setup!

 

 

 

 

[JorgeB]

You can take a snapshot and then use btrfs send/receive to another disk on the same server or to a different server, there's some info for that here, it's for a vdisk but the basics are the same.

[navinrs]

Thanks johnnie.black just saw your message. Will try this!