I have a QNAP NAS (TS-873), it has 7x4TB disks in a RAID6 with a warm spare (e.g. 7 disk raid) and it had a RAID1 NVMe SSD, but lost the riser card which means now, no more SSD.
If this was ZFS, then I'd know what I am doing but this is LVM with DRBD tiering, and despite all my googling, I can't figure out how to recover it. I really don't need it all back online, honestly I have almost everything backed up or what was hot on the cache can easily be discarded. But there are some files which should be cold on the RAID which my wife will want sooner or later, and I hadn't backed them up. So if someone can help future me stay out of trouble, I'd be grateful. The alternative is to use low level file recovery on the RAID, which at 18TB is going to take a very, very long time to scan!
The main issue is that, when I try to activate the volume it says it can't because, although the RAID6 is there, the RAID1 isn't. It says that /dev/md256 is missing and can't activate. The annoying thing is that I can't even see references to /dev/md256 in vgscan or vgdisplay! How am I supposed to detach the RAID1 if none of the commands can see it!
I'd post some output captures, but I have the machine on a testbench trying to see if it can do "testdisk" and find the ext4 fs to mount but so far it's not looking hopeful.
Does anyone have advice on how to "fix" a tiered LVM with DRBD and cache missing? I really don't care about what's hot on the cache, I just hope the fs doesn't need the cache to start.
If this was ZFS, then I'd know what I am doing but this is LVM with DRBD tiering, and despite all my googling, I can't figure out how to recover it. I really don't need it all back online, honestly I have almost everything backed up or what was hot on the cache can easily be discarded. But there are some files which should be cold on the RAID which my wife will want sooner or later, and I hadn't backed them up. So if someone can help future me stay out of trouble, I'd be grateful. The alternative is to use low level file recovery on the RAID, which at 18TB is going to take a very, very long time to scan!
The main issue is that, when I try to activate the volume it says it can't because, although the RAID6 is there, the RAID1 isn't. It says that /dev/md256 is missing and can't activate. The annoying thing is that I can't even see references to /dev/md256 in vgscan or vgdisplay! How am I supposed to detach the RAID1 if none of the commands can see it!
I'd post some output captures, but I have the machine on a testbench trying to see if it can do "testdisk" and find the ext4 fs to mount but so far it's not looking hopeful.
Does anyone have advice on how to "fix" a tiered LVM with DRBD and cache missing? I really don't care about what's hot on the cache, I just hope the fs doesn't need the cache to start.
