Use pigz if it is available, for less CPU-bound operation.

diff --git a/backup.sh b/backup.sh
index 652b4636b36b8406a2631b0f2c5f5d234b0a0232..a6ebadee9fb63c7ffda8c00b1d83946ded76949f 100755 (executable)
--- a/backup.sh
+++ b/backup.sh
@@ -89,17 +89,17 @@ backup()
  exf=`ssh root@$computer "ls ~/.backup/exclude"`
 
  # We try to run tar on the remote computer
- #    z gzip it
  #    c create archive
  #    C change to directory first
  #    . where to start taring (see C)
  #    $lastcmd only files newer than this
  #    --one-file-system don't traverse file systems
+ #    --use-compress-program compress it using gzip or pigz
  #    --exclude-from file to get exclusion pattern from
  #    Pipe the stuff over ssh to ourselves, run pee to cat the contents to a
  #    file and build a file list, respectivly.  
  TARFILE=$DATE.tmp
- TARCMD="ssh root@$computer \"nice -n 19 ionice -c3 tar --one-file-system -zcf - -C $filesystem . $lastcmd \
+ TARCMD="ssh root@$computer \"nice -n 19 ionice -c3 tar --one-file-system --use-compress-program $compressor -cf - -C $filesystem . $lastcmd \
        --exclude-from=$exf\" | pee \"cat > $TARFILE\" \"tar tzvf -\""
  echo `date`" $computer: Running $TARCMD" >&2
  eval $TARCMD > $DATE.idx
@@ -156,6 +156,14 @@ backup()
   # We don't want to return 0
   die
  fi
+
+ # Check if pigz is available
+ if ssh -n root@$computer "pigz -V 2>/dev/null"; then
+   compressor=pigz
+ else
+   echo `date`" $computer: pigz missing; falling back to gzip."
+   compressor=gzip
+ fi
  
  filesystems=""