Individuals can augment these through Time Slider, a facility that allows taking frequent snapshots of a user's data. In any sort of production environment, backups are made on a regular basis. See the beadm(1M) man page for information on how to select what BE to activate on next reboot, or any other of a number of administrative actions. ZFS snapshots, though, are immensely helpful when making any system software changes, because it is a trivial reboot to get back to the previous environment. So user directories such as /export/home are not included in a snapshot. ZFS snapshots are fast and efficient, but they are only a snapshot the Oracle Solaris part of the system (for example, anything that could be patched).
Over time as changes are made, and new blocks are modified, added, or deleted, the snapshot grows. BEs are not only fast to create, they are very economical from a storage perspective because the copy, that is, the current BE, has only blocks that are different from the original environment. The old version of a block pointed to by the BE created earlier would not be updated, but a new block would be created for the current BE with updated data. Over time, as the current Oracle Solaris environment changes, blocks might need to be rewritten. If, after some testing, the SA is not satisfied with the update, it is easy to reboot to the pre-update state.Ĭreating a BE (a copy of your current Oracle Solaris environment) is a very fast process and shows off one of the key feature of ZFS: What is initially copied are mostly pointers to data blocks in the file system, not data blocks themselves. In that case, after updating, the SA would reboot into the just-created BE containing the updated Oracle Solaris environment.
When updating packages, for example, installing the monthly Support Repository Update, a boot environment is typically automatically created and the patches will be applied to that BE, not to the running system. In the unlikely situation there is a problem from this action, the SA can reboot to safety-net-be to get back to a known working state. A BE includes all the files Oracle Solaris needs to operate.įor example, to create a snapshot of the current Oracle Solaris environment, run the following command:Īfter a snapshot has been created, the SA would then perform some action that would impact the Oracle Solaris environment, say, adding new packages. To create a snapshot (called a boot environment ), use the beadm(1M) command. There are two ways to do this: one for system administrators and one for users. The other approach is using the capability of ZFS.
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