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btrbk: always preserve latest snapshot/backup pair (instead of latest snapshot and latest backup); remove preserve_latest option of schedule()

pull/88/head
Axel Burri 2016-04-13 14:47:38 +02:00
parent 032642751b
commit 36cc96fdb8
3 changed files with 60 additions and 59 deletions
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82
btrbk
View File

@ -1807,20 +1807,30 @@ sub vinfo_subsection($$;$)
}
sub get_snapshot_children($$)
sub get_snapshot_children($$;$$)
{
my $sroot = shift || die;
my $svol = shift // die;
my $subvol_dir = shift // "";
my $btrbk_basename = shift;
my @ret;
my $sroot_subvols = vinfo_subvol_list($sroot);
foreach (@$sroot_subvols) {
next unless($_->{node}{readonly});
next unless($_->{node}{parent_uuid} eq $svol->{node}{uuid});
if(defined($btrbk_basename) &&
( (not exists($_->{BTRBK_BASENAME})) ||
($_->{SUBVOL_DIR} ne $subvol_dir) ||
($_->{BTRBK_BASENAME} ne $btrbk_basename)) ) {
TRACE "get_snapshot_children: child does not match btrbk filename scheme, skipping: $_->{PRINT}";
next;
}
TRACE "get_snapshot_children: found: $_->{PRINT}";
push(@ret, $_);
}
DEBUG "Found " . scalar(@ret) . " snapshot children of: $svol->{PRINT}";
$subvol_dir .= '/' if($subvol_dir);
DEBUG "Found " . scalar(@ret) . " snapshot children of \"$svol->{PRINT}\" in: $sroot->{PRINT}" . (defined($btrbk_basename) ? "/$subvol_dir$btrbk_basename.*" : "");
return @ret;
}
@ -2651,7 +2661,6 @@ sub schedule(@)
my %args = @_;
my $schedule = $args{schedule} || die;
my $preserve = $args{preserve} || die;
my $preserve_latest = $args{preserve_latest} || 0;
my $results_list = $args{results};
my $result_hints = $args{result_hints} // {};
@ -2699,11 +2708,6 @@ sub schedule(@)
}
}
if($preserve_latest && (scalar @sorted_schedule)) {
my $href = $sorted_schedule[-1];
$href->{preserve} ||= $preserve_latest;
}
my %first_in_delta_hours;
my %first_in_delta_days;
my %first_in_delta_weeks;
@ -4229,7 +4233,8 @@ MAIN:
foreach my $svol (vinfo_subsection($sroot, 'subvolume')) {
my $snapdir = config_key($svol, "snapshot_dir") // "";
my $snapshot_basename = config_key($svol, "snapshot_name") // die;
my $preserve_latest = $svol->{SNAPSHOT_CREATED} ? 0 : 1;
my @snapshot_children = sort({ cmp_date($a->{BTRBK_DATE}, $b->{BTRBK_DATE}) }
get_snapshot_children($sroot, $svol, $snapdir, $snapshot_basename));
foreach my $droot (vinfo_subsection($svol, 'target')) {
INFO "Checking for missing backups of subvolume \"$svol->{PRINT}\" in: $droot->{PRINT}/";
@ -4237,14 +4242,8 @@ MAIN:
my $resume_total = 0;
my $resume_success = 0;
foreach my $child (sort { $a->{node}{cgen} <=> $b->{node}{cgen} } get_snapshot_children($sroot, $svol))
foreach my $child (@snapshot_children)
{
unless($child->{BTRBK_DATE} &&
($child->{SUBVOL_DIR} eq $snapdir) &&
($child->{BTRBK_BASENAME} eq $snapshot_basename)) {
TRACE "Backup candidate does not match btrbk filename scheme, skipping: $child->{PRINT}";
next;
}
next if(scalar(get_receive_targets($droot, $child, exact_match => 1, warn_unexpected => 1)));
if(my $err_vol = vinfo_subvol($droot, $child->{NAME})) {
@ -4272,13 +4271,13 @@ MAIN:
}
push(@schedule, { value => undef,
btrbk_date => $vol->{BTRBK_DATE},
preserve => $vol->{node}{FORCE_PRESERVE},
# not enforcing resuming of latest snapshot anymore (since v0.23.0)
# preserve => $vol->{node}{FORCE_PRESERVE},
});
}
my ($preserve, undef) = schedule(
schedule => \@schedule,
preserve => config_preserve_hash($droot, "target"),
preserve_latest => $preserve_latest,
schedule => \@schedule,
preserve => config_preserve_hash($droot, "target"),
);
my @resume = grep defined, @$preserve; # remove entries with no value from list (target subvolumes)
$resume_total = scalar @resume;
@ -4324,11 +4323,12 @@ MAIN:
{
foreach my $sroot (vinfo_subsection($config, 'volume')) {
foreach my $svol (vinfo_subsection($sroot, 'subvolume')) {
my $snapdir = config_key($svol, "snapshot_dir") // "";
my $snapdir_ts = config_key($svol, "snapshot_dir", postfix => '/') // "";
my $snapshot_basename = config_key($svol, "snapshot_name") // die;
my $preserve_latest_snapshot = $svol->{SNAPSHOT_CREATED} ? 0 : "preserve forced: latest in list (no snapshot created)";
my $preserve_latest_backup = $preserve_latest_snapshot;
my $target_aborted = 0;
my @snapshot_children = sort({ cmp_date($b->{BTRBK_DATE}, $a->{BTRBK_DATE}) } # sort descending
get_snapshot_children($sroot, $svol, $snapdir, $snapshot_basename));
foreach my $droot (vinfo_subsection($svol, 'target', 1)) {
if(ABORTED($droot)) {
@ -4339,16 +4339,18 @@ MAIN:
}
next;
}
if($droot->{CONFIG}->{target_type} eq "raw") {
if(config_key($droot, "incremental")) {
# In incremental mode, the latest backup is most certainly our parent.
# (see note on FORCE_PRESERVE above)
$preserve_latest_backup ||= "preserve forced: possibly parent of latest backup";
# Note that we could check against $svol->{SNAPSHOT_CREATED}->{node}{parent_uuid} to be certain,
# but this information is not available in $dryrun:
# foreach my $vol (@{vinfo_subvol_list($droot)}) {
# $vol->{FORCE_PRESERVE} = 1 if($vol->{node}{received_uuid} eq $svol->{SNAPSHOT_CREATED}->{node}{parent_uuid});
# }
# always preserve latest common snapshot/backup pair
foreach my $child (@snapshot_children) {
my @receive_targets = get_receive_targets($droot, $child);
if(scalar(@receive_targets)) {
DEBUG "Force preserve for latest common snapshot: $child->{PRINT}";
$child->{node}{FORCE_PRESERVE} = 'preserve forced: latest common snapshot';
foreach(@receive_targets) {
DEBUG "Force preserve for latest common target: $_->{PRINT}";
$_->{node}{FORCE_PRESERVE} = 'preserve forced: latest common target';
}
last;
}
}
@ -4357,10 +4359,9 @@ MAIN:
#
INFO "Cleaning backups of subvolume \"$svol->{PRINT}\": $droot->{PRINT}/$snapshot_basename.*";
unless(macro_delete($droot, "", $snapshot_basename, $droot,
{ preserve => config_preserve_hash($droot, "target"),
preserve_latest => $preserve_latest_backup,
results => $schedule_results,
result_hints => { topic => "backup", root_path => $droot->{PATH} },
{ preserve => config_preserve_hash($droot, "target"),
results => $schedule_results,
result_hints => { topic => "backup", root_path => $droot->{PATH} },
},
commit => config_key($droot, "btrfs_commit_delete"),
type => "delete_target",
@ -4382,11 +4383,10 @@ MAIN:
next;
}
INFO "Cleaning snapshots: $sroot->{PRINT}/$snapdir_ts$snapshot_basename.*";
macro_delete($sroot, $snapdir_ts, $snapshot_basename, $svol,
{ preserve => config_preserve_hash($svol, "snapshot"),
preserve_latest => $preserve_latest_snapshot,
results => $schedule_results,
result_hints => { topic => "snapshot", root_path => $sroot->{PATH} },
macro_delete($sroot, $snapdir, $snapshot_basename, $svol,
{ preserve => config_preserve_hash($svol, "snapshot"),
results => $schedule_results,
result_hints => { topic => "snapshot", root_path => $sroot->{PATH} },
},
commit => config_key($svol, "btrfs_commit_delete"),
type => "delete_snapshot",

19
doc/btrbk.1
View File

@ -126,22 +126,23 @@ First, btrbk reads information from the source and target btrfs
filesystems in order to perform sanity checks and identify
parent/child and received-from relationships.
.PP
If the checks succeed, btrbk creates snapshots for all the source
subvolumes specified in the configuration file.
If the checks succeed, btrbk creates snapshots for the source
subvolumes specified in the configuration file, according to the
\fIsnapshot_create\fR option.
.PP
Then, for each specified target, btrbk creates the backups as follows:
After the backups in the target directory are compared to the source
snapshots, btrbk transfers all missing snapshots needed to satisfy the
configured target retention policy, incrementally from the latest
common parent subvolume found. If no common parent subvolume is found
(or if the \fIincremental\fR option is set to \[lq]no\[rq]), a full
After comparing the backups to the source snapshots, btrbk transfers
all missing snapshots needed to satisfy the configured target
retention policy, incrementally from the latest common parent
subvolume found. If no common parent subvolume is found (or if the
\fIincremental\fR option is set to \[lq]no\[rq]), a full
(non-incremental) backup is created.
.PP
As a last step, unless the \-p (\-\-preserve) option is set, snapshots
and backup subvolumes that are not preserved by their configured
retention policy will be deleted. Note that the latest snapshot (the
one created in the first step) is always preserved, regardless of the
retention policy.
one created in the first step) as well as the latest snapshot/backup
pair are always preserved, regardless of the retention policy.
.PP
Use the \fI\-\-format\fR command line option to switch between
different output formats.

18
doc/btrbk.conf.5
View File

@ -100,16 +100,16 @@ valid in the \fIsubvolume\fR section. Defaults to
\fI<subvolume-name>\fR.
.RE
.PP
\fBsnapshot_create\fR always|ondemand|onchange|no
\fBsnapshot_create\fR always|onchange|ondemand|no
.RS 4
If set to \[lq]ondemand\[rq], snapshots are only created if the target
subvolume is reachable (useful if you are tight on disk space and you
only need btrbk for backups to an external disk which is not always
connected). If set to \[lq]onchange\[rq], snapshots are only created
if the source subvolume has changed since the last snapshot (more
precisely: if the btrfs generation has been increased since the last
snapshot). If set to \[lq]always\[rq], snapshots are always
created. If set to \[lq]no\[rq], the snapshots are never created
If set to \[lq]always\[rq], snapshots are always created. If set to
\[lq]onchange\[rq], snapshots are only created if the source subvolume
has changed since the last snapshot (more precisely: if the btrfs
generation has been increased since the last snapshot). If set to
\[lq]ondemand\[rq], snapshots are only created if the target subvolume
is reachable (useful if you are tight on disk space and you only need
btrbk for backups to an external disk which is not always
connected). If set to \[lq]no\[rq], the snapshots are never created
(useful if another instance of btrbk is taking care of snapshot
creation). Defaults to \[lq]always\[rq].
.RE