README, INSTALL improvements.
[dss.git] / README
1 dss creates hardlink-based snapshots of a given directory on a remote
2 or local host using rsync's link-dest feature.
3
4 dss is admin friendly: It is easy to configure and needs little
5 attention once configured to run in daemon mode. It keeps track of
6 the available disk space and removes snapshots if disk space becomes
7 sparse or snapshots become older than the specified time.
8
9 dss is also user-friendly because users can browse the snapshot
10 directories without admin intervention and see the contents of the file
11 system at the various times a snapshot was taken. In particular, users
12 can easily restore accidently removed files by using their favorite
13 file browser to simply copy files from the snapshot directory back
14 to the live system.
15
16 dss gives your data an additional level of security besides the usual
17 tape-based backups: If the file server goes down and all data is lost
18 you can simply use the most recent snapshot as an immediate replacement
19 -- no need for a restore from tape that takes days to complete.
20
21 Snapshot pruning takes place in a dyadic fashion: Many recent snapshots
22 are available, but the number of snapshots per time interval decreases
23 exponentially. For example, one can configure dss so that it keeps
24 16 snapshots not older than one week, 8 snapshots between one and
25 two weeks old, 4 snapshots between two and three weeks old, and so on.