Ceph » CephFS

Say you enter a snapshot pseudo-dir then run:

mkdir test
rmdir test
mkdir test

then restart the mds, and run:

ls

you'll find see test isn't there any more. Oops.

now, doing something like:

mkdir test
touch ..
touch -r test ..
rmdir test
mkdir test

works (i.e., after restarting the mds the directory is still there), presumably because we're now binding the snapshot name to a different version of the directory.

Changes to files within the snapshotted directory appear to suffice to get the snapshot to survive an mds restart as well.