fix #3351: allow keeping a different number of snapshots on source and destination

by introducing a new dest-maxsnap parameter which can be used to override
maxsnap for the destination side.

This is useful for backups, as one can potentially save a lot of space on the
source side (or the destination side if one can come up with a use case for
that) by keeping fewer snapshots around.

Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>

diff --git a/pve-zsync b/pve-zsync
index 1213361ab1e2997fa80d63971ebbefc36c02ffef..39ead0de8ccadd59e36191c899381e2f5535784b 100755 (executable)
--- a/pve-zsync
+++ b/pve-zsync
@@ -244,6 +244,7 @@ sub parse_argv {
        verbose => undef,
        limit => undef,
        maxsnap => undef,
+       dest_maxsnap => undef,
        name => undef,
        skip => undef,
        method => undef,
@@ -261,6 +262,7 @@ sub parse_argv {
        'verbose' => \$param->{verbose},
        'limit=i' => \$param->{limit},
        'maxsnap=i' => \$param->{maxsnap},
+       'dest-maxsnap=i' => \$param->{dest_maxsnap},
        'name=s' => \$param->{name},
        'skip' => \$param->{skip},
        'method=s' => \$param->{method},
@@ -336,6 +338,7 @@ sub param_to_job {
     $job->{method} = "ssh" if !$job->{method};
     $job->{limit} = $param->{limit};
     $job->{maxsnap} = $param->{maxsnap};
+    $job->{dest_maxsnap} = $param->{dest_maxsnap};
     $job->{source} = $param->{source};
     $job->{source_user} = $param->{source_user};
     $job->{dest_user} = $param->{dest_user};
@@ -460,6 +463,7 @@ sub format_job {
     $text .= " root";
     $text .= " $PROGNAME sync --source $job->{source} --dest $job->{dest}";
     $text .= " --name $job->{name} --maxsnap $job->{maxsnap}";
+    $text .= " --dest-maxsnap $job->{dest_maxsnap}" if defined($job->{dest_maxsnap});
     $text .= " --limit $job->{limit}" if $job->{limit};
     $text .= " --method $job->{method}";
     $text .= " --verbose" if $job->{verbose};
@@ -681,20 +685,31 @@ sub sync {
 
            ($dest->{old_snap}, $dest->{last_snap}) = snapshot_get(
                $dest_dataset,
-               $param->{maxsnap},
+               $param->{dest_maxsnap} // $param->{maxsnap},
                $param->{name},
                $dest->{ip},
                $param->{dest_user},
            );
 
+           ($source->{old_snap}) = snapshot_get(
+               $source->{all},
+               $param->{maxsnap},
+               $param->{name},
+               $source->{ip},
+               $param->{source_user},
+           );
+
            prepare_prepended_target($source, $dest, $param->{dest_user}) if defined($dest->{prepend});
 
            snapshot_add($source, $dest, $param->{name}, $date, $param->{source_user}, $param->{dest_user});
 
            send_image($source, $dest, $param);
 
-           for my $old_snap (@{$dest->{old_snap}}) {
+           for my $old_snap (@{$source->{old_snap}}) {
                snapshot_destroy($source->{all}, $old_snap, $source->{ip}, $param->{source_user});
+           }
+
+           for my $old_snap (@{$dest->{old_snap}}) {
                snapshot_destroy($dest_dataset, $old_snap, $dest->{ip}, $param->{dest_user});
            }
        };
@@ -1157,6 +1172,9 @@ $PROGNAME create --dest <string> --source <string> [OPTIONS]
                The number of snapshots to keep until older ones are erased.
                The default is 1, use 0 for unlimited.
 
+       --dest-maxsnap   integer
+               Override maxsnap for the destination dataset.
+
        --name      string
                The name of the sync job, if not set it is default
 
@@ -1197,6 +1215,9 @@ $PROGNAME sync --dest <string> --source <string> [OPTIONS]\n
                The number of snapshots to keep until older ones are erased.
                The default is 1, use 0 for unlimited.
 
+       --dest-maxsnap   integer
+               Override maxsnap for the destination dataset.
+
        --name      string
                The name of the sync job, if not set it is 'default'.
                It is only necessary if scheduler allready contains this source.