README


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28

dss creates hardlink-based snapshots of a given directory on a remote
or local host using rsync's link-dest feature.

dss is admin friendly: It is easy to configure and needs little
attention once configured to run in daemon mode. It keeps track of
the available disk space and removes snapshots if disk space becomes
sparse or snapshots become older than the specified time. Also, due
to the hardlink-based approach, there is only one type of backup.
Hence no full, incremental or differential backups need to be
configured, and there is no database to maintain.

dss is also user-friendly because users can browse the snapshot
directories without admin intervention and see the contents of the file
system at the various times a snapshot was taken. Each snapshot looks
like a full backup, so users can easily restore accidentally removed
files by using their favorite file browser to simply copy files from
the snapshot directory back to the live system.

dss gives your data an additional level of security besides the usual
tape-based backups: If the file server goes down and all data is lost
you can simply use the most recent snapshot as an immediate replacement
-- no need for a restore from tape that takes days to complete.

Snapshot pruning takes place in a dyadic fashion: Many recent snapshots
are available, but the number of snapshots per time interval decreases
exponentially. For example, one can configure dss so that it keeps
16 snapshots not older than one week, 8 snapshots between one and
two weeks old, 4 snapshots between two and three weeks old, and so on.