Add new option --keep-redundant.

[dss.git] / dss.ggo

diff --git a/dss.ggo b/dss.ggo
index 731cabb89485418f0326611e18176bca4a982f1e..8037373321acbde3327966e9fe997a749b5c01f8 100644 (file)
--- a/dss.ggo
+++ b/dss.ggo
@@ -82,12 +82,17 @@ details="
        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
 
@@ -102,13 +107,14 @@ details="
 
 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+"Remove redundant and outdated snapshots"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+       A snapshot is considered outdated if it belongs to an interval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
@@ -208,13 +214,14 @@ details="
        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.
 "
@@ -316,3 +323,17 @@ 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+       If this flag is not given dss removes redundant and outdated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 inode ratio
+       becomes low. Use this flag if the file system containing the
+       destination directory is used for snapshots only.
+"