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Re: Talking about RAID - disks with same id




On 11/08/17 13:40, deloptes wrote:
Hi,
I noticed recently by accident that when I read/write from the oldest raid
disks I have - only one of the tray leds blinks. Of course the led could be
damaged, but rather not, so looking into it I found that both disks in
question return same UUID. So I am concerned now that I don't have any true
RAID there and that there is very important data on those disks.

How is this possible and how to solve it - I would simply add 3rd 500MB disk
to the raid and remove one of the others, but still what is the impact of
this (stupid) coincidence ...

# blkid /dev/sdf
/dev/sdf: PTUUID="13e17ac7" PTTYPE="dos"
                   ^^^^^^^^
# blkid /dev/sdg
/dev/sdg: PTUUID="13e17ac7" PTTYPE="dos"

My file server had a 1.5 TB desktop drive with LUKS and btrfs, created with Debian 7. When I rebuilt my SOHO network with Debian 8, all was well. But, when I rebuilt my SOHO network with Debian 9, I noted weirdness. I don't know if it was Debian, GNU, Linux, LUKS, btrfs, smbd, something on the client, PEBKAS, etc..


While trouble-shooting PEBKAS issues is important to me, I have found that my attempts at trouble-shooting GNU/Linux issues is usually an exercise in futility. The best I can hope for is finding a way to reproduce the issue and filing a bug report. But as for fixing an issue, my best bets is fresh software and known-good hardware.


So, for the file server issue, I built a 2 @ 1.5 TB mdadm RAID1 with LUKS and ext4 in another Debian 9 machine, tested it, backed up the file server, migrated the data, and then migrated the drives. The weirdness is now gone. :-)


We'll see what happens when I rebuild with Debian 10...


David