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Annotation of wikisrc/projects/project/tmpfs-snapshot.mdwn, revision 1.2

1.1       jmmv        1: [[!template id=project
                      2: 
                      3: title="Add snapshots to tmpfs"
                      4: 
                      5: contact="""
                      6: [tech-kern](mailto:tech-kern@NetBSD.org)
                      7: """
                      8: 
                      9: category="filesystems"
1.2     ! jmmv       10: difficulty="medium"
1.1       jmmv       11: 
                     12: description="""
                     13: Add memory-efficient snapshots to tmpfs.  A snapshot is a view of the
                     14: filesystem, frozen at a particular point in time.  The snapshotted filesystem is
                     15: not frozen, only the view is.  That is, you can continue to
                     16: read/write/create/delete files in the snapshotted filesystem.
                     17: 
                     18: The interface to snapshots may resemble the interface to null mounts, e.g.,
                     19: 'mount -t snapshot /var/db /db-snapshot' makes a snapshot of /var/db/ at
                     20: /db-snapshot/.
                     21: 
                     22: You should exploit features of the virtual memory system like copy-on-write
                     23: memory pages to lazily make copies of files that appear both in a live tmpfs and
                     24: a snapshot.  This will help conserve memory.
                     25: """
                     26: ]]