Taking a snapshot
From this point on, all the actions take place in the snapshot tab for the relevant traditional VPS in the CloudVPS Interface.
First enter the name you want to give the snapshot, and then click the 'Create' button to take the snapshot.
A snapshot is a copy of the VPS hard disk. Taking a snapshot is immediate and instantaneous. The snapshot technique does not interrupt normal operation of the VPS, nor does the snapshot have any impact on the performance of the VPS.
When the snapshot is taken it is copied to the datastore.
Conditions for a snapshot:
- The following characters can be used for a snapshot name: 0...9aA...zZ-_ (but no spaces)
- All other symbols are removed from the name and spaces are replaced with underscores (_).
- SELinux Extended attributes are not copied during these snapshots. !
- We strongly advise against taking snapshots when SELinux is on.
When a snapshot is taken it is copied to the datastore. This is a separate disk where a maximum of three free snapshots can be saved.
You can perform the following activities in the datastore:
- Deleting a snapshot.
- Copying a snapshot to the snapback partition for instant snapback. (In this case, a copy of snapshot remains in the datastore)
Restoring a snapshot with Instant Snapback
Because we want to make it possible to immediately restore a pre-selcted snapshot (instant snapback), restoring a snapshot consists of two steps:
- Copying the snapshot you want to restore from the database to the instant snapback partition (this can take a little time).
- Booting the VPS from the instant snapback partition. This occurs immediately and the old hard disk then becomes the snapback partition (until you overwrite it) so you can switch back if there is a problem.
It is not possible to access the instant snapback partition directly from the VPS.
Boot configuration / Snapback
The CloudVPS Interface clearly indicates which partition is the current hard disk (boot partition) and whether a second bootable HDD is ready (snapback partition).
At the moment the snapback takes place – booting the VPS from the snapback partition – the current boot partition will be exchanged with the snapback partition. The old boot partition then becomes the new snapback partition. You can then use this to return to the original boot partition, or you can overwrite it with a different image from the datastore.
Example: Suppose that the boot partition is 'centos55-bare.conf' (the install image) and that the snapshot '18Aug2010-MonoInstall' is copied from the datastore to the snapback partition. In this case Snapback will reboot the VPS using 'Aug2010-MonoInstall' as the boot partition and 'centos55-bare.conf' as the snapback partition. When another snapback is performed, the partitions will be exchanged again and 'centos55-bare.conf' will once again become the boot partition and 'Aug2010-MonoInstall' the snapback partition.