+# Copyright (C) 2008 Andre Noll <maan@systemlinux.org>
#
+# Licensed under the GPL v2. For licencing details see COPYING.
+
package "dss"
-version "0.0.4"
+version "0.0.5"
purpose "the dyadic snapshot scheduler
dss creates hardlink-based snapshots of a given directory on a remote
is also given.
"
+##################
+section "Commands"
+##################
+
defgroup "command"
#=================
groupdesc="
dss supports a couple of commands each of which corresponds
to a different command line option. Exactly one of these
options must be given.
+
"
required
groupoption "prune" P
#~~~~~~~~~~~~~~~~~~~~
-"Remove a redundant snapshot"
+"Remove redundant and outdated snapshots"
group="command"
details="
- A snapshot is considered redundant if it ether belongs to
- an interval greater than the maximum number of intervals,
- or if it belongs to an interval that already contains more
- than the desired number of snapshots.
+ A snapshot is considered outdated if it belongs to an interval
+ greater than the maximum number of intervals. It is said to be
+ redundant if it belongs to an interval that already contains
+ more than the desired number of snapshots. This command gets
+ rid of such snapshots.
"
groupoption "ls" L
unit intervals.
dss removes any snapshots older than n times u and tries to
- keep 2^(k-1) snapshots in interval k, where the interval number
- k counts from zero, zero being the most recent unit interval.
+ keep 2^(n - k - 1) snapshots in interval k, where the interval
+ number k counts from zero, zero being the most recent unit
+ interval.
In other words, the oldest snapshot will at most be u * n days
(= 20 days if default values are used) old. Moreover, there
are at most 2^n - 1 snapshots in total (i. e. 31 by default).
- Observe that you have to create at least 2 ^ (n - 1) snapshots
+ Observe that you have to create at least 2^(n - 1) snapshots
each interval for this to work out because that is the number
of snapshots in interval zero.
"
optional
details="
Execute this after a snapshot has successfully been
- created. The full path of the newly created snapshot is passed
- to the hook as the first argument. The return value of that
- hook is ignored.
+ created. The full path of the newly created snapshot is
+ passed to the hook as the first argument. The exit code of
+ this hook is ignored.
For instance this hook can be used to count the number of
files per user and/or the disk usage patterns in order to
- store them in a database for further treatment.
+ store them in a database for further analysis.
"
###############################
details="
Specify the minimum amount of free inodes on the file system
containing the destination dir. If less than that many inodes
- are free, snatshot removal kicks in just as in case of low
+ are free, snapshot removal kicks in just as in case of low
disk space.
Note that not every file system supports the concept of inodes.