Data Recovery

Introduction

With Ceph's RBD snapshots, we are able to restore RBD images to previous states in order to recover data.

Ceph RBD

On a Ceph admin node, (substitute <IMAGE NAME> with the appropriate image path e.g. virtual-machines/steeltoe)

1. find the appropriate image by running rbd ls

2. list all the image's snapshots by running rbd snap ls <IMAGE NAME> and gain information about the image with rbd info <IMAGE NAME> .

3. disable necessary features with rbd feature disable <IMAGE NAME> object-map fast-diff

4. enable layering for RBD copy-on-write (http://docs.ceph.com/docs/master/dev/rbd-layering/) with rbd feature enable <IMAGE NAME> layering

5. using the image snapshot name obtained in step 2

For example to restore an image named virtual-machines/steeltoe from the snapshot 20190108 :

rbd feature disable virtual-machines/steeltoe object-map fast-diff
cd /mnt
mkdir steeltoe
rbd map virtual-machines/steeltoe@20190108
mount /dev/rbd/virtual-machines/steeltoe-part1@20180108 /mnt/steeltoe
# Obtain the necessary files from /mnt/steeltoe
umount /mnt/steeltoe
rbd unmap virtual-machines/steeltoe
rbd feature enable virtual-machines/steeltoe object-map fast-diff

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