Flash Disk Failed Without Backup

[weird.turned.pro]

Woke up this morning to my server offline and unable to reboot to unRAID - when I pulled the USB flash drive and plug into another machine it's coming up as RAW.

 

I've gone out and got a new USB flash drive, flashed unRAID onto it and read this wiki article, which brings me here to figure out how to not nuke all my data on the array on reboot. So, what do I need to know to keep from destroying all my data on the array?

 

I'm pretty sure I know which disks were members of data and cache, but does the order they were added to the array matter?

 

Painful lesson learned - hoping to recover safely and do better future-forward.

Edited December 8, 2019 by weird.turned.pro
grammar/spelling

[trurl]

The most important is to not assign a data disk to parity. How many cache disks do you have? 

[weird.turned.pro]

I have 4 cache disks that are all part of a Sun Microsystems Flash Accelerator.

 

4 x 200GB in RAID 10 BTRFS.

[trurl]

So you know exactly which disks are cache then?

 

Do you have a screenshot that might show your disk assignments? Did you ever save a syslog or diagnostics?

[weird.turned.pro]

Yes, the disks that are part of the cache set should be very distinguishable from data and parity. I don't have any logs/screenshots unfortunately, but I'm fairly certain all disks were added in order (e.g. sda, sdb, sdc, etc.)

 

EDIT: Will I need to do anything prior to reboot to assure the cache set stays in RAID10 and doesn't get reformatted?

Edited December 8, 2019 by weird.turned.pro
Additional info

[Squid]

2 minutes ago, weird.turned.pro said:

(e.g. sda, sdb, sdc, etc.)

Never count on the sdX designators staying the same.  They can change from one boot to another.

[weird.turned.pro]

Shoot - I was wondering about that. Will ordering matter - or just assuring disks aren't mixed between data, parity and cache?

[Squid]

For data, order doesn't particularly matter.  If you get it wrong and have a parity 2 drive, then parity will wind up being invalid, which just means you rebuild it.  No clue though about cache and RAID 10

[trurl]

2 hours ago, Squid said:

No clue though about cache and RAID 10

I think we need @johnnie.black on this thread.

[JorgeB]

Cache pool just needs all members assigned at array start and existing pool will be used, there can't be a "all data on this device" will be deleted warning for any of the cache devices.

[trurl]

You can always download a zipped backup of flash from Main - Boot Device - Flash - Flash Backup. Your configuration is completely contained in the config folder on flash, and if you can copy that folder to a new install you would be running again just as before.

 

You should make a new backup anytime you make any significant configuration changes, especially when you make any changes to disk assignments.