UNIX Machine Backups Backups Using Windows Media at the AOC Backups to DVD/CDRs Snapshots |
Snapshots - what are these and where?The Network Appliance " In your Unix home directory on the filer, there is a directory called
Within each of these hourly or nightly snapshots is a complete copy of how your files appeared at that time. This is a read-only copy, meaning you can browse the files, and/or copy them to "normal" (non-snapshot) locations such as your real home directory, but you cannot write to them, nor can you manually place files in the snapshot directories. Windows users cannot easily browse these directories from an explorer window by clicking, but the files and subdirectories are there; you may have to enter the directory explicitly (by typing it in, e.g. via the RUN command from the START menu). While it may appear that we're wasting huge amounts of space with these snapshots, we're not, really. The "WAFL" file system on the NetApp is constructed in such a way that the snapshots are like incremental backups; they really only contain the changes and differences -- at the disk block level -- between your current files and how they appeared at the time of the snapshot. If the file hasn't changed, they'll be identical and take up no extra space. Content reviewed on: 5-May-2011
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