rzerres/dsnap-sync
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snap-sync: btrfs-send/btrfs-receive pipe handling

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- snapper is using hardcoded subvolume name to store its ro snapshots
  variable snapper_snapshots holds it (.snapshots)
- new optional progress visualiation (via pv)
- more robust error handling
  rely on btrfs-send/btrfs-receive exit code
This commit is contained in:
Ralf Zerres
2017-11-22 13:11:59 +01:00
parent 62a33aa88b
commit ec4723d65d
1 changed files with 93 additions and 38 deletions
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131
bin/snap-sync
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@@ -33,11 +33,18 @@ version="0.4.4"
SNAPPER_CONFIG=/etc/conf.d/snapper
SNAPPER_TEMPLATES=/etc/snapper/config-templates
TMPDIR=$(mktemp -d)
PIPE=$TMPDIR/$progname.out
# define fifo pipes
TMPDIR_PIPE=$(mktemp -d)
PIPE=$TMPDIR_PIPE/$progname.out
mkfifo $PIPE
systemd-cat -t "$progname" < $PIPE &
exec 3>$PIPE
systemd-cat --identifier="$progname" < $PIPE &
BTRFS_PIPE=$TMPDIR_PIPE/btrfs.out
#mkfifo $BTRFS_PIPE
#systemd-cat --identifier="btrfs-pipe" < $BTRFS_PIPE &
# redirect descriptors to given pipes
exec 3>$PIPE 4>$BTRFS_PIPE
# global variables
donotify=0
@@ -50,6 +57,7 @@ disk_uuid_match=''
selected_uuid='none'
selected_target='none'
selected_subvol='none'
snapper_snapshots=".snapshots" # hardcoded in snapper
###
# functions
@@ -68,6 +76,7 @@ check_prerequisites () {
# optional binaries:
which notify-send >/dev/null 2>&1 && { donotify=1; }
which pv >/dev/null 2>&1 && { do_pv_cmd=1; }
if [ $(id -u) -ne 0 ] ; then printf "Script must be run as root" ; exit 1 ; fi
@@ -283,9 +292,12 @@ parse_params () {
;;
--remote)
remote=$2
ssh="ssh $remote"
shift 2
;;
--remote=*)
remote=${1#*=}
shift
;;
--subvolid=*|--SUBVOLID=*)
subvolid_cmdline=${1#*=}
shift
@@ -325,6 +337,8 @@ parse_params () {
if [ -z $remote ]; then
ssh=""
else
ssh="ssh $remote"
fi
if [ "$verbose" ]; then
@@ -529,42 +543,83 @@ run_backup () {
verify_snapper_structure "backup_root=$backup_root" "snapper_target_config=$snapper_target_config" "snapper_new_id=$snapper_new_id"
snapper_target_snapshot_size=$(du --sum $snapper_new_snapshot 2>/dev/null | awk -F ' ' '{print $1}')
# settings for interactive progress status
if [ $do_pv_cmd ]; then
pv_options="--delay-start 2 --interval 5 --timer --rate --bytes --fineta --progress"
cmd_pv="pv $pv_options --size $snapper_target_snapshot_size |"
#cmd_pv="pv $pv_options --size $snapper_target_snapshot_size | dialog --gauge \"$progname: Progress for config '$selected_config'\" 6 85 |"
else
cmd_pv=''
fi
if [ -z "$snapper_sync_id" ]; then
cmd="btrfs send $snapper_new_snapshot | $ssh btrfs receive $snapper_target_snapshot"
printf "Sending first snapshot for snapper config '%s' ...\n" "$selected_config" | tee $PIPE
if [ "$verbose" ]; then
printf "btrfs send %s | %s btrfs receive %s\n" "$snapper_new_snapshot" "$ssh" "$snapper_target_snapshot"
cmd="btrfs send -v $snapper_new_snapshot | $ssh btrfs receive -v $snapper_target_snapshot"
# target never received any snapshot before
if [ "$verbose" ]; then
printf "Sending first snapshot for snapper config '%s' (size=%s) ...\n" "$selected_config" "$snapper_target_snapshot_size"
fi
cmd="btrfs send $verbose_flag $snapper_new_snapshot 2>$BTRFS_PIPE | $cmd_pv $ssh btrfs receive $verbose_flag $snapper_target_snapshot 2>$BTRFS_PIPE"
if [ ! "$dryrun" ]; then
btrfs send "$snapper_new_snapshot" | $ssh btrfs receive "$snapper_target_snapshot" &>/dev/null
sync
# this could take a while, depending on datasize
$(eval $cmd)
if [ "$?" -gt 0 ]; then
printf "BTRFS_PIPE: %s" "cat $BTRFS_PIPE"
die "btrfs pipe error."
fi
else
cmd="btrfs send -v $snapper_new_snapshot | $ssh btrfs receive -v $snapper_target_snapshot"
printf "dryrun: %s\n" "$cmd"
printf "dryrun: %s\n" "$cmd"
fi
else
printf "Sending incremental snapshot for snapper config '%s' ...\n" "$selected_config" | tee $PIPE
# Sends the difference between the new snapshot and old snapshot to the
# backup location. Using the -c flag instead of -p tells it that there
# is an identical subvolume to the old snapshot at the receiving
# location where it can get its data. This helps speed up the transfer.
verbose_flag="-v"
if [ ! "$dryrun" ]; then
btrfs send "$verbose_flag" -c "$snapper_sync_snapshot" "$snapper_new_snapshot" | $ssh btrfs receive "$verbose_flag" "$snapper_target_snapshot"
if [ "$verbose" ]; then
printf "Deleting sync snapshot for %s ...\n" "$selected_config" | tee $PIPE
fi
snapper -c "$selected_config" delete "$snapper_sync_id"
sync
if [ "$verbose" ]; then verbose_flag="-v"; fi
printf "Sending incremental snapshot for snapper config '%s' ...\n" "$selected_config"
# checking if parent snapshot-id (as saved on source) is also available on target
if $ssh [ -d "$backup_root/$snapper_target_config/$snapper_snapshots/$snapper_sync_id" ]; then
# Sends the difference between the new snapshot and old synced snapshot to the
# backup location. Using the -c (clone-source) flag instead of -p (parent) tells it
# that there is an identical subvolume to the synced snapshot at the receiving
# location where it can get its data. This helps speed up the transfer.
if [ ! "$dryrun" ]; then
if [ "$verbose" ]; then
printf "btrfs-send will use targets snapshot '%s' to sync metadata for %s ...\n" "$snapper_sync_snapshot" "$snapper_new_snapshot"
fi
cmd="btrfs send $verbose_flag -c $snapper_sync_snapshot $snapper_new_snapshot 2>$BTRFS_PIPE | $cmd_pv $ssh btrfs receive $verbose_flag $snapper_target_snapshot 2>/dev/null"
ret=$(eval $cmd)
if [ "$?" -gt 0 ]; then
printf "BTRFS_PIPE: %s" "cat $BTRFS_PIPE"
die "btrfs pipe error."
fi
else
printf "dryrun: btrfs send %s -c %s %s | %s btrfs receive %s %s\n" \
"$verbose_flag" "$snapper_sync_snapshot" "$snapper_new_snapshot" \
"$ssh" "$verbose_flag" "$snapper_target_snapshot"
printf "dryrun: snapper --config %s delete %s\n" "$selected_config" "$snapper_sync_id"
fi
else
printf "dryrun: btrfs send %s -c %s %s | %s btrfs receive %s %s\n" \
"$verbose_flag" "$snapper_sync_snapshot" "$snapper_new_snapshot" \
"$ssh" "$verbose_flag" "$snapper_target_snapshot"
printf "dryrun: snapper --config %s delete %s\n" "$selected_config" "$snapper_sync_id"
# need to use source snapshot to provide metadata for target
if [ ! "$dryrun" ]; then
if [ "$verbose" ]; then
printf "btrfs-send is using source snapshot '%s' to read metadata ...\n" "$snapper_sync_snapshot" | tee $PIPE
printf "Deleting old sync snapshot %s for %s ...\n" "$snapper_sync_id" "$selected_config" | tee $PIPE
fi
cmd="btrfs send $verbose_flag -p $snapper_sync_snapshot $snapper_new_snapshot 2>$BTRFS_PIPE | $cmd_pv $ssh btrfs receive $verbose_flag $snapper_target_snapshot 2>/dev/null"
$(eval $cmd)
ret=$(eval $cmd)
if [ "$?" -gt 0 ]; then
printf "BTRFS_PIPE: %s" "cat $BTRFS_PIPE"
die "btrfs pipe error."
fi
#printf "btrfs returns: '%i'\n" "$ret"
else
printf "dryrun: btrfs send %s -c %s %s | %s btrfs receive %s %s\n" \
"$verbose_flag" "$snapper_sync_snapshot" "$snapper_new_snapshot" \
"$ssh" "$verbose_flag" "$snapper_target_snapshot"
printf "dryrun: snapper --config %s delete %s\n" "$selected_config" "$snapper_sync_id"
fi
fi
fi
# finally: send the snapper info metadata
if [ -z "$ssh" ]; then
if [ ! "$dryrun" ]; then
cp "$snapper_new_info" "$snapper_target_snapshot"
@@ -626,19 +681,20 @@ run_finalize () {
# which is stored in snappers info.xml file of the source snapshot.
# This is how we find the parent.
userdata="backupdir=$backup_dir, subvolid=$selected_subvol, uuid=$selected_uuid"
src_host=$(eval cat /etc/hostname)
src_uuid=$(eval findmnt --noheadings --output UUID $SUBVOLUME)
src_subvolid=$(eval findmnt --noheadings --output OPTIONS $SUBVOLUME | sed -e 's/.*subvolid=\([0-9]*\).*/\1/')
userdata="backupdir=$backup_dir, subvolid=$selected_subvol, uuid=$selected_uuid, host=$remote"
target_description="snap-sync backup"
target_userdata="subvolid=$src_subvolid, uuid=$src_uuid, host=$src_host"
# Tag new snapshot as the latest
# Tag new snapshots key/value parameter
printf "Tagging snapper metadata for configuration '%s' ...\n" "$selected_config" | tee $PIPE
if [ ! "$dryrun" ]; then
eval snapper --verbose --config "$selected_config" modify --description \"$description\" --userdata \"$userdata\" "$snapper_new_id"
$(eval snapper --verbose --config "$selected_config" modify --description \"$description\" --userdata \"$userdata\" "$snapper_new_id")
sync
$ssh snapper --verbose --config "$snapper_target_config" modify --description \"$target_description\" --userdata \"$target_userdata\" "$snapper_new_id"
#TODO: wait for btrfs-receive to be completed!
$ssh "snapper --verbose --config $snapper_target_config modify --description \"$target_description\" --userdata \"$target_userdata\" $snapper_new_id"
$ssh sync
else
cmd="snapper -v -c $selected_config modify -d $description -u $userdata $snapper_new_id"
@@ -654,6 +710,7 @@ run_finalize () {
sync
printf "Backup complete for snapper configuration '%s'.\n" "$selected_config" > $PIPE
done
}
@@ -751,8 +808,8 @@ select_target_disk () {
if [ "$verbose" ]; then
printf "Selected Subvol-ID=%s: %s on %s\n" "$selected_subvol" "$selected_target" "$selected_uuid"
fi
}
}
traperror () {
printf "Exited due to error on line %s.\n" $1
printf "exit status: %s\n" "$2"
@@ -798,8 +855,6 @@ verify_snapper_structure () {
local snapper_config=${2##snapper_target_config=}
local snapper_id=${3##snapper_new_id=}
local snapper_snapshots=".snapshots"
if [ "$verbose" ]; then
printf "Verify snapper filesystem structure on target ...\n"
fi