VDB ZFS Snapshot Administration
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Contents |
Background
What are snapshots?
Snapshots enable you to take a instant point-in-time version of your entire Virtual Server's hard-drive, and preserve it indefinitely. Once you have created a snapshot of your Virtual Server's hard-drive, you can continue to use your Virtual Server normally.
If you decide that you ever want to return your Virtual Server back to the exact state that it was in when you took a snapshot, you can perform a rollback operation. Rolling back to an existing snapshot has the effect of "discarding" any and all changes that occurred to your Virtual Server since you took the snapshot. In effect, a snapshot is like a backup that you can "snap back" to in a matter of seconds.
Why are snapshots useful? What can I use them for?
Snapshots can be a useful supplement to a regular backup scheme. Although they do not necessarily replace traditional backups, they can offer very quick recovery, especially in controlled environments such as software upgrades or patches.
For example, consider the following scenarios:
- Performing large and/or complicated software upgrades: Migrating from Apache 1.x to 2.x, for example. Simply take a snapshot when your Virtual Server is in a working state, and then perform the upgrade. If you have any problems, you can instantly revert back to the previous environment.
- Learning and Investigation: Moving up to administering a Virtual Server can be a challenging experience for less experienced system administrators. With the VDB Snapshots, users can confidently explore and practice making changes to their system, knowing that they can instantly revert their system back to a "known good state" when they have finished. Want to practice setting up an LDAP Server? A J2EE Environment? How about a Proxy Server? When you're done, you can simply rollback to your previous "clean" state, and try something else.
Overview
When you click on the "Snapshots" section of the Virtual Server tab in VDB, you will see a screen similar to this:
Image:VDB Snapshot Overview.jpg
From this screen, you can manage your Virtual Server's snapshot(s). If you select one of the buttons, a confirmation dialog box will appear, explaining what is about to happen, and asking you to confirm your request before a snapshot is created, deleted or rolled back to.
