iankelling.org Git - distro-setup/blob - btrbk-run

   1 #!/bin/bash
   2 # Copyright (C) 2016 Ian Kelling
   3
   4 # Licensed under the Apache License, Version 2.0 (the "License");
   5 # you may not use this file except in compliance with the License.
   6 # You may obtain a copy of the License at
   7
   8 #     http://www.apache.org/licenses/LICENSE-2.0
   9
  10 # Unless required by applicable law or agreed to in writing, software
  11 # distributed under the License is distributed on an "AS IS" BASIS,
  12 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13 # See the License for the specific language governing permissions and
  14 # limitations under the License.
  15
  16
  17 # todo: if we cancel in the middle of a btrfs send, then run again
  18 # immediately, the received subvolume doesn't get a Received UUID:
  19 # field, and we won't mount it. Need to figure out a solution that will
  20 # fix this.
  21
  22
  23 [[ $EUID == 0 ]] || exec sudo -E "${BASH_SOURCE[0]}" "$@"
  24
  25 source /usr/local/lib/err
  26
  27 usage() {
  28   cat <<'EOF'
  29 btrbk-run [OPTIONS] [run|resume|archive]
  30 usually -t TARGET_HOST or -s SOURCE_HOST
  31
  32 Note, at source location, intentionally not executable, run and read
  33 install-my-scripts.
  34
  35 EOF
  36   echo "top of script file:"
  37   sed -n '1,/^[# ]*end command line/{p;b};q' "$0"
  38   exit $1
  39 }
  40
  41
  42
  43 script_name="${BASH_SOURCE[0]}"
  44 script_name="${script_name##*/}"
  45 pre="${SSH_CLIENT:+$HOSTNAME} $script_name:"
  46 m() { if $verbose; then printf "$pre%s\n"  "$*"; fi;  "$@"; }
  47 e() { printf "$pre%s\n"  "$*"; }
  48 die() { printf "$pre%s\n" "$*" >&2; echo "exiting with status 1" >&2; exit 1; }
  49 mexit() { echo "$pre: exiting with status $1"; exit $1; }
  50
  51 # latest $MAIL_HOST
  52 if [[ -e /b/bash_unpublished/source-state ]]; then
  53   source /b/bash_unpublished/source-state
  54 fi
  55
  56 # note q is owned by root:1000
  57
  58 mountpoints=()
  59
  60 rsync_mountpoint=/q
  61
  62 ret=0
  63 # default options
  64 conf_only=false
  65 dry_run=false # mostly for testing
  66 rate_limit=no
  67 verbose=true; verbose_arg=-v
  68 if [[ $INVOCATION_ID ]]; then
  69   # INVOCATION_ID means running as a systemd service. we cant show progress in this case,
  70   # but if we pass the arg, it will insert mbuffer into the command.
  71   progress_arg=
  72 else
  73   progress_arg="--progress"
  74 fi
  75 incremental_strict=false
  76 pull_reexec=false
  77
  78 default_args_file=/etc/btrbk-run.conf
  79 if [[ -s $default_args_file ]]; then
  80   # shellcheck disable=SC2046 # we want word splitting
  81   set -- $(< $default_args_file) "$@"
  82   # i havent used this feature yet, so warn about it
  83   echo "$0: warning: default btrbk-run options set in $default_args_file (sleeping 5 seconds):"
  84   cat $default_args_file
  85   sleep 5
  86 fi
  87
  88 targets=()
  89 early=false
  90 cron=false
  91 fast=false
  92 kd_spread_maybe=false
  93 orig_args=("$@")
  94 temp=$(getopt -l cron,fast,pull-reexec,help 23ceikl:m:npqrs:t:vh "$@") || usage 1
  95 eval set -- "$temp"
  96 while true; do
  97   case $1 in
  98     # some behaviors specific to running under cron:
  99     # - skip hosts where xprintidle haven't been idle recently
 100     # - if we can't ssh to 1 or more hosts, still do the rest
 101     # - if we aren't MAIL_HOST and no -m or -s, just exit
 102     --cron)
 103       cron=true
 104       pre=
 105       ;;
 106     # for the rare case we want to run multiple instances at the same time
 107     -2) conf_suf=2 ;;
 108     -3) conf_suf=3 ;;
 109     # only creates the config file, does not run btrbk
 110     -c) conf_only=true ;;
 111     # quit early, just btrbk, no extra remounting etc.
 112     -e) early=true ;;
 113     # skip various checks. when we run twice in a row for
 114     # switch mail-host, no need to repeat the same checks again.
 115     --fast) fast=true ;;
 116     -i) incremental_strict=true ;;
 117     # note this implies resume
 118     -k) kd_spread_maybe=true ;;
 119     # bytes per second, suffix k m g
 120     -l) rate_limit=$2; shift ;;
 121     # Comma separated mountpoints to backup. This has defaults set below.
 122     -m) IFS=, mountpoints=($2); unset IFS; shift ;;
 123     -n) dry_run=true ;;
 124     # hide progress
 125     -p) progress_arg= ;;
 126     # internal option for rerunning under newer SOURCE_HOST version.
 127     --pull-reexec) pull_reexec=true;;
 128     # quiet
 129     -q) verbose=false; verbose_arg=; progress_arg= ;;
 130     # source host to receive a backup from
 131     -s)
 132       source=$2
 133       bbksource=$source
 134       if [[ $source == *:* ]]; then
 135         bbksource="[$source]"
 136       fi
 137       shift
 138       ;;
 139     # target hosts to send to. empty is valid for just doing local
 140     # snapshot. we have default hosts we will populate.
 141     -t) IFS=, targets=($2); unset IFS; shift ;;
 142     # verbose.
 143     -v) verbose=true; verbose_arg=-v ;;
 144     -h|--help) usage ;;
 145     --) shift; break ;;
 146     *) die "Internal error!" ;;
 147   esac
 148   shift
 149 done
 150
 151 if $kd_spread_maybe; then
 152   if [[ $1 && $1 != resume ]]; then
 153     die "dont pass -k without resume or empty run arg"
 154   fi
 155   cmd_arg=resume
 156 fi
 157
 158
 159 cmd_arg=${1:-run}
 160
 161
 162 std_preserve="36h 14d 8w 24m"
 163 q_preserve="18h 14d 8w"
 164
 165 case $cmd_arg in
 166   run|resume) : ;;
 167
 168   # This works better than the normal archive command. We have to
 169   # specify the mount points, but that is what we are used to doing and
 170   # we prefer it. Another difference is that archive works recursively
 171   # and we don't care about that. Sometimes we may still want to run
 172   # btrbk archive, but it doesn't even use the config file, so just
 173   # run it directly, eg:
 174   # time s btrbk -v archive /mnt/r7/amy/boot/btrbk ssh://bo/mnt/boot2/btrbk
 175   archive)
 176     cmd_arg=resume
 177     std_preserve="999h 999d 999w 999m"
 178     q_preserve="$std_preserve"
 179     preserve_arg=-p
 180     ;;
 181   *) die "untested command arg" ;;
 182 esac
 183
 184 if (( $# > 1 )); then
 185   die: "only 1 nonoption arg is supported"
 186 fi
 187
 188 if [[ -v targets && $source ]]; then
 189   # note, this doesnt need to be the case, but
 190   # we would need to think about it.
 191   die "error: -t and -s are mutually exclusive"
 192 fi
 193
 194 ### end options parsing
 195
 196 # remove path from earlier version of btrbk
 197 rm -f /usr/sbin/btrbk
 198 # note, this still works as intended if there is no /usr/bin/btrbk
 199 if [[ /a/opt/btrbk/btrbk -nt /usr/bin/btrbk ]]; then
 200   if [[ -e /b/distro-functions/src/package-manager-abstractions ]]; then
 201     . /b/distro-functions/src/package-manager-abstractions
 202     pi asciidoctor
 203   fi
 204   cd /a/opt/btrbk
 205   m make install
 206 fi
 207
 208 # TODO: i wonder if there should be an option to send to the default
 209 # targets, plus any given on the command line.
 210
 211
 212
 213 kd_spread=false
 214 # set default targets
 215 if [[ ! -v targets && ! $source ]]; then
 216   if $cron; then
 217     if [[ $HOSTNAME != "$MAIL_HOST" ]]; then
 218       if $kd_spread_maybe && [[ $HOSTNAME == kd && $MAIL_HOST == x3 ]]; then
 219         if ping -q -c1 -w1 x3.office.fsf.org &>/dev/null; then
 220           work_host=x3.office.fsf.org
 221         elif ping -q -c1 -w1 x3wg.b8.nz &>/dev/null; then
 222           work_host=x3wg.b8.nz
 223         fi
 224         if [[ $work_host ]]; then
 225           source_state="$(ssh $work_host cat /a/bin/bash_unpublished/source-state)"
 226           eval "$source_state"
 227           if [[ $MAIL_HOST == x3 ]]; then
 228             kd_spread=true
 229           else
 230             # x3 was the mail host, but it moved to some other machine
 231             # without updating us yet.
 232             echo "MAIL_HOST=$MAIL_HOST, nothing to do"
 233             mexit 0
 234           fi
 235         else
 236           echo "MAIL_HOST=$MAIL_HOST, nothing to do"
 237           mexit 0
 238         fi
 239       else
 240         echo "MAIL_HOST=$MAIL_HOST, nothing to do"
 241         mexit 0
 242       fi
 243     fi
 244   fi
 245
 246   at_work=false
 247   at_home=false
 248
 249   case $HOSTNAME in
 250     kw|kd|frodo|x2|x3|sy) : ;;
 251     *)
 252       die "error: no default targets for this host, use -t"
 253       ;;
 254   esac
 255
 256   case $HOSTNAME in
 257     kw)
 258       at_work=true
 259       ;;&
 260     kd|frodo)
 261       at_home=true
 262       ;;&
 263     x2|x3|sy)
 264       if [[ $(dig +short @10.2.0.1 -x 10.2.0.2 2>&1 ||:) == kd.b8.nz. ]] \
 265            && ip n show 10.2.0.1 | grep . &>/dev/null; then
 266         at_home=true
 267       elif ping -q -c1 -w1 hal.office.fsf.org &>/dev/null \
 268           && ip n show 192.168.0.26 | grep . &>/dev/null; then
 269         at_work=true
 270       fi
 271       ;;&
 272     *)
 273       if $at_home; then
 274         if ! $kd_spread && [[ $HOSTNAME != x3 ]]; then
 275           # main work machine
 276           if ping -q -c1 -w1 x3.office.fsf.org &>/dev/null; then
 277             targets+=(x3.office.fsf.org)
 278           elif ping -q -c1 -w1 $h.b8.nz &>/dev/null; then
 279             # in case we took it home
 280             targets+=(x3.b8.nz)
 281           else
 282             targets+=(x3wg.b8.nz)
 283           fi
 284         fi
 285         # temporarily disabled while doing recovery
 286         #        for h in frodo kd; do
 287         for h in kd; do
 288           if [[ $HOSTNAME == "$h" ]]; then
 289             continue
 290           fi
 291           targets+=($h.b8.nz)
 292         done
 293         for h in x2 sy; do
 294           if [[ $HOSTNAME == "$h" ]]; then
 295             continue
 296           fi
 297           if ping -q -c1 -w1 $h.b8.nz &>/dev/null; then
 298             targets+=($h.b8.nz)
 299           elif ping -q -c1 -w1 ${h}w.b8.nz &>/dev/null; then
 300             targets+=(${h}w.b8.nz)
 301           fi
 302         done
 303       elif $at_work; then
 304         targets+=(i.b8.nz)
 305         for h in x2 x3 kw; do
 306           if [[ $HOSTNAME == "$h" ]]; then
 307             continue
 308           fi
 309           if ping -q -c1 -w1 $h.office.fsf.org &>/dev/null; then
 310             targets+=($h.office.fsf.org)
 311           fi
 312         done
 313       else
 314         targets+=(i.b8.nz)
 315       fi
 316       ;;
 317   esac
 318 fi
 319
 320 if $verbose; then
 321   printf "$pre options: conf_only=%s\ndry_run=%s\nrate_limit=%s\nverbose=%s\ncmd_arg=%s" "$conf_only" "$dry_run" "$rate_limit" "$verbose" "$cmd_arg"
 322 fi
 323
 324
 325 if [[ -v targets ]]; then
 326   echo "targets: ${targets[*]}"
 327 fi
 328
 329 if [[ $source ]]; then
 330   echo "source: $source"
 331 fi
 332
 333 if [[ ${mountpoints[0]} ]]; then
 334   for mp in ${mountpoints[@]}; do
 335     if [[ -e /nocow/btrfs-stale/$mp ]]; then
 336       die "error: $mp is stale, mount-latest-subvol first"
 337     fi
 338   done
 339 else
 340   # set default mountpoints
 341   if [[ ${targets[0]} == tp ]]; then
 342     prospective_mps=(/a)
 343   else
 344     case $HOSTNAME in
 345       *)
 346         prospective_mps=()
 347         if [[ $source ]]; then
 348           source_state="$(ssh $source cat /a/bin/bash_unpublished/source-state)"
 349           eval "$source_state"
 350           source_host="$(ssh $source cat /etc/hostname)"
 351           if [[ $source_host == "$MAIL_HOST" ]]; then
 352             prospective_mps+=(/o)
 353           fi
 354           if [[ $source_host == "$HOST2" ]]; then
 355             prospective_mps+=(/a /ar /qr /q)
 356           fi
 357         else
 358           if [[ $HOSTNAME == "$MAIL_HOST" ]]; then
 359             prospective_mps+=(/o)
 360           fi
 361           if [[ $HOSTNAME == "$HOST2" ]]; then
 362             prospective_mps+=(/a /ar /qr /q)
 363           fi
 364           if $kd_spread; then
 365             prospective_mps=(/a /ar /o /qr /q)
 366           fi
 367         fi
 368         # note: put q last just in case its specific retention options were to
 369         # affect other config sections. I havent tested if that is the case.
 370         ;;
 371     esac
 372   fi
 373   for mp in ${prospective_mps[@]}; do # default mountpoints to sync
 374     if [[ -e /nocow/btrfs-stale/$mp ]]; then
 375       e "warning: $mp stale, not adding to default mountpoints"
 376       continue
 377     fi
 378     if awk '{print $2}' /etc/fstab | grep -xF $mp &>/dev/null; then
 379       mountpoints+=($mp)
 380     fi
 381   done
 382 fi
 383
 384 if (( ! ${#mountpoints[@]} )); then
 385   die didnt get mountpoint arg and had no defaults
 386 fi
 387
 388 echo "mountpoints: ${mountpoints[*]}"
 389
 390 ##### end command line parsing ########
 391
 392 # todo: this has a timing problem, since btrbk.timer could activate the service after this check.
 393 if ! $fast && [[ $source ]]; then
 394   if [[ $(ssh $source ps --no-headers -o comm 1) == systemd ]]; then
 395     status=$(ssh $source systemctl is-active btrbk.service) || : # normally returns 3
 396     case $status in
 397       inactive|failed) : ;;
 398       *)
 399         echo "$0: error: cron btrbk is running on source. exiting out of caution"
 400         mexit 1
 401     esac
 402   fi
 403 fi
 404
 405 # pull_reexec stops us from getting into an infinite loop if there is some
 406 # kind of weird problem
 407 pulla=false
 408 for m in "${mountpoints[@]}"; do
 409   if [[ $m == /a ]]; then
 410     pulla=true
 411     break
 412   fi
 413 done
 414 if ! $pull_reexec && [[ $source ]] && $pulla ; then
 415   tmpf=$(mktemp)
 416   m rsync -ra $source:/usr/local/bin/{mount-latest-subvol,check-subvol-stale} /usr/local/bin
 417   m rsync -ra $source:/usr/local/lib/err /usr/local/lib
 418   m scp $source:/a/bin/distro-setup/btrbk-run $tmpf
 419   if ! diff -q $tmpf ${BASH_SOURCE[0]}; then
 420     e "found different version on host $source. reexecing"
 421     install -T $tmpf /usr/local/bin/btrbk-run
 422     m /usr/local/bin/btrbk-run --pull-reexec "${orig_args[@]}"
 423     mexit 0
 424   fi
 425 fi
 426
 427
 428 if ! command -v btrbk &>/dev/null; then
 429   die "error: no btrbk binary found"
 430 fi
 431
 432 if ! $fast; then
 433   # if our mountpoints are from stale snapshots,
 434   # it doesn't make sense to do a backup.
 435   m check-subvol-stale ${mountpoints[@]} || die "found stale mountpoints in ${mountpoints[*]}"
 436
 437   # for an initial run, btrbk requires the dir to exist.
 438   mkdir -p /mnt/{root,o}/btrbk
 439 fi
 440 local_zone=$(date +%z)
 441
 442 if [[ $source ]]; then
 443   if $fast; then
 444     zone=$local_zone
 445   else
 446     if ! zone=$(ssh root@$source date +%z); then
 447       if $conf_only; then
 448         echo "$0: warning: failed to ssh to root@$source"
 449       else
 450         die failed to ssh to root@$source
 451       fi
 452     fi
 453     if [[ $zone != "$local_zone" ]]; then
 454       die "error: dont confuse yourself with multiple time zones. $h has different timezone than localhost"
 455     fi
 456   fi
 457 else
 458
 459   sshable=()
 460   sshfail=()
 461   for h in ${targets[@]}; do
 462     if $fast || $conf_only; then
 463       # Use some typical values in this case
 464       root_size=$(( 1024 * 1024 * 2000 )) #2tb
 465       percent_used=10
 466       zone=$(date +%z)
 467     elif remote_str=$(timeout -s 9 6 ssh root@$h "mkdir -p /mnt/root/btrbk /mnt/o/btrbk && date +%z && df --output=size,pcent / | tail -n1"); then
 468       mapfile -t tmp_array <<<"$remote_str"
 469       zone="${tmp_array[0]}"
 470       IFS=" " read -r root_size percent_used <<<"${tmp_array[1]}"
 471       percent_used=${percent_used%%%}
 472
 473       if (( ${#tmp_array[@]} != 2 )); then
 474         die "error: didnt get 2 lines in test ssh to target $h. investigate"
 475       fi
 476       case $percent_used in
 477         [0-9]|[1-9][0-9]) : ;;
 478         *)
 479           die "error: didnt get percent disk use in test ssh to target $h. investigate"
 480           ;;
 481       esac
 482     else
 483       sshfail+=($h)
 484       continue
 485     fi
 486
 487     # we may be booted into a bootstrap fs or something
 488     min_root_kb=$(( 1024 * 1024 * 200 )) # 200 gb
 489     if (( root_size < min_root_kb )); then
 490       continue
 491     fi
 492
 493     if (( percent_used >= 98 )); then
 494       die "error: filesystem on target $h is $percent_used % full"
 495     fi
 496
 497     # on sy, xprintidle is resetting every 12 seconds even when not
 498     # idle, i dunno why, instead we are checking if the screen is locked,
 499     # which is good enough.
 500     #
 501     # This is a separate ssh because the command can fail and thatis ok.
 502     if $cron; then
 503       locked=false
 504       if lock_info=$(timeout -s 9 6 ssh $h DISPLAY=:0 xscreensaver-command -time); then
 505         if [[ $lock_info != *non-blanked* ]]; then
 506           locked=true
 507         fi
 508       else
 509         locked=true
 510       fi
 511       if ! $locked; then
 512         # Ignore this host. i sometimes use a non-main machine for
 513         # testing or web browsing, knowing that everything will be wiped
 514         # by the next backup, but I dont want it to happen as Im using
 515         # it from cronjob.
 516         e "warning: $h: seems to be actively in use, skipping for now"
 517         continue
 518       fi
 519     fi
 520     sshable+=($h)
 521     if [[ $zone != "$local_zone" ]]; then
 522       die "error: dont confuse yourself with multiple time zones. $h has different timezone than localhost"
 523     fi
 524   done
 525   if [[ ! ${sshable[*]} ]] || { ! $cron && [[ ${sshfail[*]} ]]; }; then
 526     die "failed to ssh to hosts: ${sshfail[*]}"
 527   else
 528     if [[ ${sshfail[*]} ]]; then
 529       ret=1
 530       e "error: failed to ssh to ${sshfail[*]} but continuing with other hosts"
 531     fi
 532     targets=(${sshable[@]})
 533   fi
 534 fi
 535
 536
 537 cat >/etc/btrbk$conf_suf.conf <<EOF
 538 ssh_identity /q/root/h
 539 #ssh_identity /root/.ssh/home
 540
 541 # Just a guess that local7 is a good facility to pick.
 542 # It's a bit odd that the transaction log has to be logged to
 543 # a file or syslog, while other output is sent to std out.
 544 # The man does not mention a way for them to be together, but
 545 # I dunno if setting a log level like warn might also output
 546 # transaction info.
 547 transaction_syslog local7
 548
 549 # trying this out
 550 #stream_compress zstd
 551
 552 # so we only run one at a time
 553 lockfile                   /var/lock/btrbk$conf_suf.lock
 554
 555 # default format of short does not accomidate hourly preservation setting
 556 timestamp_format long-iso
 557
 558 # only make a snapshot if things have changed
 559 snapshot_create onchange
 560 # I could make this different from target_preserve,
 561 # if one disk had less space.
 562 # for now, keeping them equal.
 563 snapshot_preserve $std_preserve
 564 snapshot_preserve_min 6h
 565 snapshot_dir btrbk
 566 # so, total backups = ~58
 567 target_preserve $std_preserve
 568 target_preserve_min 6h
 569
 570 # i tried this when investigating: clone no source subvolume found error
 571 #incremental_prefs sro:1 srn:1 sao san:1 aro:1 arn:1
 572
 573 # if something fails and it's not obvious, try doing
 574 # btrbk -l debug -v dryrun
 575
 576 rate_limit $rate_limit
 577 EOF
 578
 579 if $incremental_strict; then
 580   cat >>/etc/btrbk$conf_suf.conf <<EOF
 581 incremental strict
 582 EOF
 583 fi
 584
 585 qconf() {
 586   case $sub in
 587     q)
 588       # q has sensitive data i dont want to backup for so long
 589       cat >>/etc/btrbk$conf_suf.conf <<EOF
 590 snapshot_preserve $q_preserve
 591 snapshot_preserve_min 2h
 592 snapshot_dir btrbk
 593 target_preserve $q_preserve
 594 target_preserve_min 2h
 595 EOF
 596       ;;
 597   esac
 598
 599 }
 600
 601 # make /q be last
 602 mp_count=${#mountpoints[@]}
 603 for (( i=0; i < mp_count - 1 ; i++ )); do
 604   if [[ ${mountpoints[i]} == /q ]]; then
 605     unset "mountpoints[i]"
 606     mountpoints+=(/q)
 607   fi
 608 done
 609
 610 for m in ${mountpoints[@]}; do
 611   case $m in
 612     /o)
 613       vol=/mnt/o
 614       ;;
 615     *)
 616       vol=/mnt/root
 617       ;;
 618   esac
 619
 620   sub=${m#/}
 621   if [[ $source ]]; then
 622     cat >>/etc/btrbk$conf_suf.conf <<EOF
 623 volume ssh://$bbksource$vol
 624 subvolume $sub
 625 EOF
 626     qconf
 627     cat >>/etc/btrbk$conf_suf.conf <<EOF
 628 target send-receive $vol/btrbk
 629 EOF
 630   fi
 631   if (( ${#targets[@]} )); then
 632     cat >>/etc/btrbk$conf_suf.conf <<EOF
 633 volume $vol
 634 subvolume $sub
 635 EOF
 636     qconf
 637     for tg in ${targets[@]}; do
 638       # handle ipv6
 639       if [[ $tg == *:* ]]; then
 640         tg="[$tg]"
 641       fi
 642       cat >>/etc/btrbk$conf_suf.conf <<EOF
 643 target send-receive ssh://$tg$vol/btrbk
 644 EOF
 645     done
 646   fi
 647 done
 648
 649 # todo: umount first to ensure we don't have any errors
 650 # todo: do some kill fuser stuff to make umount more reliable
 651
 652
 653 if $conf_only; then
 654   mexit 0
 655 fi
 656
 657
 658
 659 if $dry_run; then
 660   m btrbk -c /etc/btrbk$conf_suf.conf -v -n $cmd_arg
 661   mexit 0
 662 fi
 663 # -q and just using the syslog option seemed nice,
 664 # but it doesn't show when a send has a parent and when it doesn't.
 665 m btrbk -c /etc/btrbk$conf_suf.conf $preserve_arg $verbose_arg $progress_arg $cmd_arg
 666
 667 if $early; then
 668   exit 0
 669 fi
 670
 671 # todo: tp not valid anymore.
 672 # if we have it, sync to systems which don't
 673 if mountpoint $rsync_mountpoint >/dev/null; then
 674   for tg in ${targets[@]}; do
 675     case $tg in
 676       tp)
 677         dirs=(/p/c/machine_specific/tp)
 678         for x in /p/c/machine_specific/*.hosts; do
 679           if grep -qxF $tg $x; then
 680             dirs+=(${x%.hosts})
 681           fi
 682         done
 683         m rsync -aSAXPH --specials --devices --delete --relative ${dirs[@]} root@$tg:/
 684         ;;
 685     esac
 686   done
 687 fi
 688
 689 subvols=()
 690 for mp in "${mountpoints[@]}"; do
 691   subvols+=("${mp##*/}")
 692 done
 693 if [[ $source ]]; then
 694   m mount-latest-subvol "${subvols[@]}"
 695 else
 696   for tg in ${targets[@]}; do
 697     m /a/exe/mount-latest-remote "$tg" "${subvols[@]}" || ret=$?
 698   done
 699 fi
 700
 701 if [[ $ret == 0 ]]; then
 702   for tg in ${targets[@]}; do
 703     ssh root@$tg /usr/local/bin/mail-backup-clean
 704   done
 705 fi
 706
 707 mexit $ret
 708
 709 # todo: move variable data we don't care about backing up
 710 # to /nocow and symlink it.
 711
 712
 713 # background on btrbk timezones. with short/long, timestamps use local time.
 714 # for long, if your local time moves backwards, by moving timezones or
 715 # for an hour when daylight savings changes it, you will temporarily get
 716 # a more aggressive retention policy for the overlapping period, and
 717 # vice versa for the opposite timezone move. The alternative is using
 718 # long-iso, which puts timezone info into the timestamp, which means
 719 # that instead of shifting time, you shift the start of day/week/month
 720 # which is used for retention to your new local time, which means for
 721 # example, if you moved forward by 8 hours, the daily/weekly/monthly
 722 # retention will be 8 hours more aggressive since midnight is at a new
 723 # time, unless you fake the timzeone using the TZ env variable.
 724 # However, in the short term, there will be no inconsistencies.
 725 # I don't see any problem with shifting when the day starts for
 726 # retention, so I'm using long-iso.
 727
 728 # note to create a long-iso timestamp: date +%Y%m%dT%H%M%S%z