I re-did these tests this morning, since I was unsure if I could have made some mistake last night - I was tired. There results were about the same - complete data loss. As for curiousity, I also tried to skip the expand phase after creating the initial raid5 on top of the raid1. After creating it, I stopped it and recreated the old raid1 with --assume-clean. This worked well - no errors from mount or fsck. So I guess it was the mdadm --grow --raid-devices=4 that was the final nail in the coffin. I just hope you find a way to backup your files next time. I'm quite sure we've all been there - thought we were smart enough or something and the shit hit the fan and no - we weren't. Vennlig hilsen roy -- Roy Sigurd Karlsbakk (+47) 98013356 http://blogg.karlsbakk.net/ GPG Public key: http://karlsbakk.net/roysigurdkarlsbakk.pubkey.txt -- Hið góða skaltu í stein höggva, hið illa í snjó rita. ----- Original Message ----- > From: "Roy Sigurd Karlsbakk" <roy@xxxxxxxxxxxxx> > To: "Jorge Nunes" <jorgebnunes@xxxxxxxxx> > Cc: "Linux Raid" <linux-raid@xxxxxxxxxxxxxxx> > Sent: Tuesday, 5 April, 2022 02:29:03 > Subject: Re: RAID 1 to RAID 5 failure >> Didn't do a backup :-( > > First mistake… *Always* keep a backup (or three) > >> >> Unmount everything: > > No need - what you should have done, was just to grow the array by > > Partition the new drives exactly like the old ones > mdadm --add /dev/md0 /dev/sd[cd]1 # note that sd[cd] means sdc and sdd, but can > be written this way on the commandline > mdadm --grow --level=5 --raid-devices=4 > > This would have grown and converted the array to raid5 without any data loss. > >> $ sudo mdadm --create /dev/md0 -a yes -l 5 -n 2 /dev/sda /dev/sdd > > As earlier mentioned, this is to create a new array, not a conversion. > >> So, my question is: Is there a chance to redo the array correctly >> without losing the information inside? Is it possible to recover the >> 'lost' partition that existed on RAID 1 to be able to do a convenient >> backup? Or the only chance is to have a correct disk alignment inside >> the array to be able to use photorec to recover the files correctly? > > As mentioned, it doesn't look promising, but there are a few things that can be > tried. > > Your data may still reside on the sda1 and sdd1, but since it was converted to > RAID-5, the data would have been distributed among the two drives and not being > the same on both. Further growing the raid, would move the data around to the > other disks. I did a small test here on some vdisks to see if this could be > reversed somehow and see if I could find the original filesystem. I could - but > it was terribly corrupted, so not a single file remained. > > If this was valuable data, there might be a way to rescue them, but I fear a lot > is overwritten already. Others in here (or other places) may know more about > how to fix this, though. If you find out how, please tell. It'd be interesting > to learn :) > > PS: I have my personal notebook for technical stuff at > https://wiki.karlsbakk.net/index.php/Roy's_notes in case you might find that > interesting. There's quite a bit about storage there. Simply growing a raid is > apparently forgotten, since I thought that was too simple. I'll add it. > > So hope you didn't lose too much valuable data > > Vennlig hilsen / Best regards > > roy > -- > Roy Sigurd Karlsbakk > (+47) 98013356 > -- > I all pedagogikk er det essensielt at pensum presenteres intelligibelt. Det er > et elementært imperativ for alle pedagoger å unngå eksessiv anvendelse av > idiomer med xenotyp etymologi. I de fleste tilfeller eksisterer adekvate og > relevante synonymer på norsk.
