Add dss.1 and dss.1.html to .gitignore.

[dss.git] / dss.ggo

diff --git a/dss.ggo b/dss.ggo
index b5eeba8352b9c116b00565487c5af0389c14c6cd..7afa4ca94237c70b17563ce206d125372dfead7a 100644 (file)
--- a/dss.ggo
+++ b/dss.ggo
@@ -1,6 +1,9 @@
+# Copyright (C) 2008 Andre Noll <maan@systemlinux.org>

 #
 #

+# Licensed under the GPL v2. For licencing details see COPYING.
+

 package "dss"
 package "dss"

-version "0.0.4"
+version "0.1.0"

 purpose "the dyadic snapshot scheduler
 
 dss creates hardlink-based snapshots of a given directory on a remote
 purpose "the dyadic snapshot scheduler
 
 dss creates hardlink-based snapshots of a given directory on a remote


@@ -79,12 +82,17 @@ details="
        is also given.
 "
 
        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.
 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
 
 "
 required
 


@@ -99,13 +107,14 @@ details="
 
 groupoption "prune" P
 #~~~~~~~~~~~~~~~~~~~~
 
 groupoption "prune" P
 #~~~~~~~~~~~~~~~~~~~~

-"Remove a redundant snapshot"
+"Remove redundant and outdated snapshots"

 group="command"
 details="
 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+       A snapshot is considered outdated if it belongs to an interval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
 "
 
 groupoption "ls" L


@@ -124,7 +133,9 @@ groupoption "run" R
 group="command"
 details="
        This is the main mode of operation. Snapshots will be created
 group="command"
 details="
        This is the main mode of operation. Snapshots will be created

-       as needed and pruned automatically.
+       in an endless loop as needed and pruned automatically. The loop
+       only terminates on fatal errors or if a terminating signal was
+       received. See also the --exit-hook option.

 "
 
 ###############################
 "
 
 ###############################


@@ -205,13 +216,14 @@ details="
        unit intervals.
 
        dss removes any snapshots older than n times u and tries to
        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).
 
        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.
 "
        each interval for this to work out because that is the number
        of snapshots in interval zero.
 "


@@ -252,13 +264,29 @@ string typestr="command"
 optional
 details="
        Execute this after a snapshot has successfully been
 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
 
        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.
+"
+
+option "exit-hook" e
+#~~~~~~~~~~~~~~~~~~~
+"Executed if run command exits"
+string typestr="command"
+optional
+details="
+       This hook is only used if the --run command was given which
+       instructs dss to run in an endless loop. The exit-hook gets
+       executed whenever this endless loop terminates. The reason
+       for terminating the loop is passed as the first argument.
+
+       One possible application for this hook is to send email to the
+       system administrator to let her know that no more snapshots
+       are going to be created.

 "
 
 ###############################
 "
 
 ###############################


@@ -303,7 +331,7 @@ optional
 details="
        Specify the minimum amount of free inodes on the file system
        containing the destination dir. If less than that many inodes
 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.
        disk space.
 
        Note that not every file system supports the concept of inodes.


@@ -313,3 +341,17 @@ details="
 
        A value of zero (the default) deactivates this check.
 "
 
        A value of zero (the default) deactivates this check.
 "

+
+option "keep-redundant" k
+#~~~~~~~~~~~~~~~~~~~~~~~~
+"Prune by disk space only"
+flag off
+details="
+       If this flag is not given dss removes redundant and outdated
+       snapshots automatically.
+
+       Otherwise, this feature is deactivated so that snapshots
+       are only being removed in case disk space or inode ratio
+       becomes low. Use this flag if the file system containing the
+       destination directory is used for snapshots only.
+"