Fix removal of orphaned snapshots.

[dss.git] / dss.ggo

diff --git a/dss.ggo b/dss.ggo
index 7892d530c3a689a1edb665e84d6f9472f387884c..3133d037dc4f8a6ed5f035bd180e29b8d32597ad 100644 (file)
--- a/dss.ggo
+++ b/dss.ggo
@@ -3,7 +3,7 @@
 # Licensed under the GPL v2. For licencing details see COPYING.
 
 package "dss"
-version "0.0.5"
+version "0.1.2"
 purpose "the dyadic snapshot scheduler
 
 dss creates hardlink-based snapshots of a given directory on a remote
@@ -133,7 +133,9 @@ groupoption "run" R
 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.
 "
 
 ###############################
@@ -193,8 +195,12 @@ string typestr="option"
 optional
 multiple
 details="
-       These option may be given multiple times. The arguments passed
-       to that option are passed verbatim to the rsync command.
+       This option may be given multiple times. The given argument is
+       passed verbatim to the rsync command. Note that in order to use
+       rsync options that require an argument, you have to specify the
+       option and its argument as separate --rsync-options, like this:
+
+               --rsync-option --exclude --rsync-option /proc
 "
 
 ###################
@@ -271,6 +277,55 @@ details="
        store them in a database for further analysis.
 "
 
+option "pre-remove-hook" -
+#~~~~~~~~~~~~~~~~~~~~~~~~~~
+"Executed before snapshot removal"
+string typestr="command"
+optional
+details="
+       Execute this command before removing a snapshot. The full
+       path to the snapshot about to be deleted is passed to the
+       command as the first argument. If the command returns with
+       a non-zero exit status, no snapshot is being removed and the
+       operation is retried later.
+
+       For example, one might want to execute a script that checks
+       whether the snapshot to be deleted is currently used by
+       another process, e.g. by a tape-based backup system that runs
+       concurrently to dss.
+
+       Another possible application of this is to record disk-usage
+       patterns before and after snapshot removal.
+"
+
+option "post-remove-hook" -
+#~~~~~~~~~~~~~~~~~~~~~~~~~~
+"Executed after snapshot removal"
+string typestr="command"
+optional
+details="
+       Execute this after a snapshot has successfully been removed. As
+       for the pre-remove hook, the full path of the removed snapshot
+       is passed to the hook as the first argument. The exit code
+       of this hook is ignored.
+"
+
+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.
+"
+
 ###############################
 section "Disk space monitoring"
 ###############################
@@ -323,3 +378,17 @@ details="
 
        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 number of free inodes
+       becomes low. Use this flag if the file system containing the
+       destination directory is used for snapshots only.
+"