Appologies if this gets posted twice. Gmail seems to be having issues. All, This may be a Fedora problem or an LVM problem, but I think it's more likely to be a pilot-error issue. Nonetheless, I hope someone here can shed some light on the following puzzling situation: To resolve a disagreement on IRC as to whether or not an LV had to be mounted ro to take a snapshot of it I decided to experiment by running the following with the lv still mounted rw: sudo lvcreate -s -L 50M -n test /dev/mapper/vg0-home I used the /dev/mapper name because that's what showed up in df's output. In retrospect this was dumb because I had never seen /dev/mapper before and am still fuzzy on it now. Google produces lots of references to it but few explanations. Anyway the error I got when doing this seemed pretty harmless (don't remember the specifics, though) so I next did: sudo lvcreate -s -L 50M -n test /dev/vg0/home This complained about there not being enough free PEs (only two free) to create the requested snapshot. So, figuring I only needed the snap long enough to see if it would create, I ran: sudo lvcreate -s -l 2 -n test /dev/vg0/home Sadly (ok, stupidly) I didn't write down exactly what happened next. All I remember is that an error was generated saying something along the lines of "couldn't recover logical volume 'home'", without much else to explain why said recovery was necessary. Sure enough any attempt to access /home, like 'ls /home', hung indefinitely. I should have let things alone then and asked for help, but it's a desktop system without any especially important information on it and I was curious. So I rebooted the system and sure enough found myself dumped to the emergency prompt. I commented /home out of fstab and now the system boots but /dev/vg0/home simply does not exist. The snapshot, /dev/vg0/test does exist, but lvdisplay describes its status as "INACTIVE destination for /dev/vg0/home". The system is running FC2 (up2dated). I realize that this isn't much to go on, but if anyone has any insight as to what happened and how/if I can get back the lost data I'd appreciate it. There was nothing vital on the LV but it bothers me that I could do so much damage so easily and I'd really like to know what went wrong. Even if it looks like I didn't do anything that could cause this I'd still like to hear it just so I know I'm not crazy! =;) Thanks, --Brad
