Removing a gluster volume doesn’t remove the volume’s contents

I made another interesting discovery this weekend while playing around with the gluster volume deletion option. Prior to creating a volume with a new layout, I went through the documented process to remove my volume:

$ gluster volume stop glustervol01
Stopping volume will make its data inaccessible. Do you want to continue? (y/n) y
Stopping volume glustervol01 has been successful

$ gluster volume delete glustervol01
Deleting volume will erase all information about the volume. Do you want to continue? (y/n) y
Deleting volume glustervol01 has been successful

I then re-created it using the documented process:

$ gluster volume create glustervol01 replica 2 transport tcp
fedora-cluster01.homefetch.net:/gluster/vol01
fedora-cluster02.homefetch.net:/gluster/vol01

Creation of volume glustervol01 has been successful. Please start the volume to access data.

$ gluster volume start glustervol01
Starting volume glustervol01 has been successful

Once the new volume was created and started I mounted in on my clients. When I went to access the volume I was quite intrigued to find that the data that was written to the previous gluster volume was still present:

$ ls -l

total 24
drwxr-xr-x 126 root root 12288 Nov 26  2011 etc
drwxr-xr-x 126 root root  4096 Nov 26 13:07 etc2
drwxr-xr-x 126 root root  4096 Nov 26 13:07 etc3
drwx------   2 root root  4096 Nov 26  2011 lost+found

Ey? Since ‘gluster delete volume’ spit out the message “Deleting volume will erase all information about the volume”, I figured the contents of the volume would be nuked (never assume, always confirm!). That doesn’t appear to be the case here. When you delete a volume the metadata that describes the volume is the only thing that is removed. It would be helpful if the developers noted this in the output above. I can see this causing headaches for folks down the road.

3 thoughts on “Removing a gluster volume doesn’t remove the volume’s contents”

  1. Makes sense considering that Gluster isn’t a file system, but instead a filesystem replication and distribution layer. Without XFS or ExtN under it, there’s nothing for it to do.

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