lvm + snapshots + uuid = assbitten

Something was strange after a recent reboot—a certain partition didn't seem to have its current contents in it.

I soon discovered that instead of mounting the filesystem, an lvm snapshot of the filesystem was mounted instead

This occurred because I had an fstab line of the form

UUID=821f....  /store/whatever
and both the original filesystem and the snapshot have the same UUID!

This is perhaps obvious when you think about what an lvm snapshot is, but it sure led to an unexpected result!

Lesson: when using lvm, specify mounts using the /dev/pvname/lvname notation unless you're sure you'll never use snapshots.

Entry first conceived on 14 October 2012, 21:23 UTC, last modified on 14 October 2012, 21:27 UTC
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