rebalancing is now optional and by default off - slows down system

btrfs-snapshots.sh

@@ -2,9 +2,15 @@
 
 # defaults
 HOURLY_DEL=25
+HOURLY_FAST=1
 DAILY_DEL=8
+DAILY_FAST=0
 WEEKLY_DEL=5
+WEEKLY_FAST=1
 MONTHLY_DEL=
+MONTHLY_FAST=1
+FAST=0
+REBALANCE=0
 BTRFS_VOLUMES=${BTRFS_VOLUMES:-$(awk '!/^#/ && $3=="btrfs" {print $2}' /etc/fstab | tr '\n' ' ' | sed 's, $,,')}
 TMP_MNT=${TMP_MNT:-/var/tmp/btrfs-backup}
 
@@ -20,7 +26,8 @@ fi
 vols=()
 del=${DEL}
 dryrun=0
-fast=0
+fast=${FAST}
+rebalance=${REBALANCE}
 periodity=${0%/*}
 periodity=${periodity##*/}
 if [[ $periodity =~ ^cron\... ]]; then
@@ -30,10 +37,10 @@ else
 fi
 
 case "$periodity" in
-    (.hourly) del=${HOURLY_DEL}; fast=1;;
-    (.daily) del=${DAILY_DEL};;
-    (.weekly) del=${WEEKLY_DEL}; fast=1;;
-    (.monthly) del=${MONTHLY_DEL}; fast=1;;
+    (.hourly) del=${HOURLY_DEL}; fast=${HOURLY_FAST};;
+    (.daily) del=${DAILY_DEL}; fast=${DAILY_FAST};;
+    (.weekly) del=${WEEKLY_DEL}; fast=${WEEKLY_FAST};;
+    (.monthly) del=${MONTHLY_DEL}; fast=${MONTHLY_FAST};;
 esac
 while test $# -gt 0; do
     case "$1" in
@@ -45,6 +52,7 @@ OPTIONS
   -h, --help         show this help
   -n, --dry-run      execute dry run, do not backup, just show commands
   -f, --fast         fast run, do not optimize btrfs (otherwise done daily)
+  -r, --rebalance    enable rebalancing (always disabled in fast mode)
   -p, --path <path>  add a path that contains a btrfs (sub-) volume
                      (defaults to: ${BTRFS_VOLUMES})
   -m, --mnt <path>   temporary mount point (default: ${TMP_MNT})
@@ -81,6 +89,7 @@ EOF
                     exit;;
         (-n|--dry-run) dryrun=1;;
         (-f|--fast) fast=1;;
+        (-r|--rebalance) rebalance=1;;
         (-p|--path) shift; vols+=( "$1" );;
         (-m|--mnt) shift; TMP_MNT="$1";;
         (-d|--del) shift; del="$1";;
@@ -135,7 +144,9 @@ for fs in ${BTRFS_VOLUMES}; do
             echo " " umount "$TMP_MNT"
             if test $fast -eq 0; then
                 echo " " btrfs filesystem defragment ${fs}
-                echo " " btrfs balance start ${fs}
+                if test $rebalance -eq 1; then
+                    echo " " btrfs balance start ${fs}
+                fi
             fi
         else
             sudo btrfs subvolume snapshot "${TMP_MNT}${subvol}" "${TMP_MNT}${target}${date}"
@@ -149,8 +160,10 @@ for fs in ${BTRFS_VOLUMES}; do
         if test $fast -eq 0; then
             echo "Defragment subvolume: '${fs}'"
             sudo btrfs filesystem defragment ${fs}
-            echo "Rebalance subvolume: '${fs}'"
-            sudo btrfs balance start ${fs}
+            if test $rebalance -eq 1; then
+                echo "Rebalance subvolume: '${fs}'"
+                sudo btrfs balance start ${fs}
+            fi
         fi
     else
         echo "ERROR: no device found for $fs" 1>&2