From 8a2a673c58ddbc1b222ec65a75c4db77b9e8b4e4 Mon Sep 17 00:00:00 2001
From: Attie Grande <attie@attie.co.uk>
Date: Sat, 6 Jan 2018 11:01:44 +0000
Subject: [PATCH 01/24] fixed loud 'NEWEST SNAPSHOT' message

---
 syncoid | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/syncoid b/syncoid
index 7337f5b..d039d15 100755
--- a/syncoid
+++ b/syncoid
@@ -597,7 +597,7 @@ sub getnewestsnapshot {
 	my $snaps = shift;
 	foreach my $snap ( sort { $snaps{'source'}{$b}{'creation'}<=>$snaps{'source'}{$a}{'creation'} } keys %{ $snaps{'source'} }) {
 		# return on first snap found - it's the newest
-		print "NEWEST SNAPSHOT: $snap\n";
+		if (!$quiet) { print "NEWEST SNAPSHOT: $snap\n"; }
 		return $snap;
 	}
 	# must not have had any snapshots on source - looks like we'd better create one!

From e902df1ef2347aa08aeb20478a2b988695dd5d20 Mon Sep 17 00:00:00 2001
From: Attie Grande <attie@attie.co.uk>
Date: Sat, 6 Jan 2018 11:03:02 +0000
Subject: [PATCH 02/24] also made warnings quiet

---
 syncoid | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/syncoid b/syncoid
index d039d15..aec99cd 100755
--- a/syncoid
+++ b/syncoid
@@ -452,13 +452,13 @@ sub checkcommands {
 
 	if ($avail{'sourcecompress'} eq '') {
 		if ($compressargs{'rawcmd'} ne '') {
-			print "WARN: $compressargs{'rawcmd'} not available on source $s- sync will continue without compression.\n";
+			if (!$quiet) { print "WARN: $compressargs{'rawcmd'} not available on source $s- sync will continue without compression.\n"; }
 		}
 		$avail{'compress'} = 0;
 	}
 	if ($avail{'targetcompress'} eq '') {
 		if ($compressargs{'rawcmd'} ne '') {
-			print "WARN: $compressargs{'rawcmd'} not available on target $t - sync will continue without compression.\n";
+			if (!$quiet) { print "WARN: $compressargs{'rawcmd'} not available on target $t - sync will continue without compression.\n"; }
 		}
 		$avail{'compress'} = 0;
 	}
@@ -471,7 +471,7 @@ sub checkcommands {
 	# corner case - if source AND target are BOTH remote, we have to check for local compress too
 	if ($sourcehost ne '' && $targethost ne '' && $avail{'localcompress'} eq '') {
 		if ($compressargs{'rawcmd'} ne '') {
-			print "WARN: $compressargs{'rawcmd'} not available on local machine - sync will continue without compression.\n";
+			if (!$quiet) { print "WARN: $compressargs{'rawcmd'} not available on local machine - sync will continue without compression.\n"; }
 		}
 		$avail{'compress'} = 0;
 	}
@@ -479,7 +479,7 @@ sub checkcommands {
 	if ($debug) { print "DEBUG: checking availability of $mbuffercmd on source...\n"; }
 	$avail{'sourcembuffer'} = `$sourcessh $lscmd $mbuffercmd 2>/dev/null`;
 	if ($avail{'sourcembuffer'} eq '') {
-		print "WARN: $mbuffercmd not available on source $s - sync will continue without source buffering.\n";
+		if (!$quiet) { print "WARN: $mbuffercmd not available on source $s - sync will continue without source buffering.\n"; }
 		$avail{'sourcembuffer'} = 0;
 	} else {
 		$avail{'sourcembuffer'} = 1;
@@ -488,7 +488,7 @@ sub checkcommands {
 	if ($debug) { print "DEBUG: checking availability of $mbuffercmd on target...\n"; }
 	$avail{'targetmbuffer'} = `$targetssh $lscmd $mbuffercmd 2>/dev/null`;
 	if ($avail{'targetmbuffer'} eq '') {
-		print "WARN: $mbuffercmd not available on target $t - sync will continue without target buffering.\n";
+		if (!$quiet) { print "WARN: $mbuffercmd not available on target $t - sync will continue without target buffering.\n"; }
 		$avail{'targetmbuffer'} = 0;
 	} else {
 		$avail{'targetmbuffer'} = 1;
@@ -500,14 +500,14 @@ sub checkcommands {
 		$avail{'localmbuffer'} = `$lscmd $mbuffercmd 2>/dev/null`;
 		if ($avail{'localmbuffer'} eq '') {
 			$avail{'localmbuffer'} = 0;
-			print "WARN: $mbuffercmd not available on local machine - sync will continue without local buffering.\n";
+			if (!$quiet) { print "WARN: $mbuffercmd not available on local machine - sync will continue without local buffering.\n"; }
 		}
 	}
 
 	if ($debug) { print "DEBUG: checking availability of $pvcmd on local machine...\n"; }
 	$avail{'localpv'} = `$lscmd $pvcmd 2>/dev/null`;
 	if ($avail{'localpv'} eq '') {
-		print "WARN: $pvcmd not available on local machine - sync will continue without progress bar.\n";
+		if (!$quiet) { print "WARN: $pvcmd not available on local machine - sync will continue without progress bar.\n"; }
 		$avail{'localpv'} = 0;
 	} else {
 		$avail{'localpv'} = 1;

From c0c30500765395cd22f975abb198ce3d4fb1d1f3 Mon Sep 17 00:00:00 2001
From: Christoph Klaffl <christoph@phreaker.eu>
Date: Tue, 19 Jun 2018 18:21:06 +0200
Subject: [PATCH 03/24] added option for skipping the parent dataset in
 recursive replication

---
 README.md | 4 ++++
 syncoid   | 8 +++++++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index cc75bdf..7392fa7 100644
--- a/README.md
+++ b/README.md
@@ -126,6 +126,10 @@ As of 1.4.18, syncoid also automatically supports and enables resume of interrup
 
 	This will also transfer child datasets.
 
++ --skip-parent
+
+	This will skip the syncing of the parent dataset. Does nothing without '--recursive' option.
+
 + --compress <compression type>
 
 	Currently accepted options: gzip, pigz-fast, pigz-slow, lzo (default) & none. If the selected compression method is unavailable on the source and destination, no compression will be used.
diff --git a/syncoid b/syncoid
index 999ee79..5cbc1c4 100755
--- a/syncoid
+++ b/syncoid
@@ -19,7 +19,7 @@ use Sys::Hostname;
 my %args = ('sshkey' => '', 'sshport' => '', 'sshcipher' => '', 'sshoption' => [], 'target-bwlimit' => '', 'source-bwlimit' => '');
 GetOptions(\%args, "no-command-checks", "monitor-version", "compress=s", "dumpsnaps", "recursive|r",
                    "source-bwlimit=s", "target-bwlimit=s", "sshkey=s", "sshport=i", "sshcipher|c=s", "sshoption|o=s@",
-                   "debug", "quiet", "no-stream", "no-sync-snap", "no-resume") or pod2usage(2);
+                   "debug", "quiet", "no-stream", "no-sync-snap", "no-resume", "skip-parent") or pod2usage(2);
 
 my %compressargs = %{compressargset($args{'compress'} || 'default')}; # Can't be done with GetOptions arg, as default still needs to be set
 
@@ -141,6 +141,11 @@ sub getchilddatasets {
 	my @children = <FH>;
 	close FH;
 
+	if (defined $args{'skip-parent'}) {
+		# parent dataset is the first element
+		shift @children;
+	}
+
 	return @children;
 }
 
@@ -1137,6 +1142,7 @@ Options:
 
   --compress=FORMAT     Compresses data during transfer. Currently accepted options are gzip, pigz-fast, pigz-slow, lzo (default) & none
   --recursive|r         Also transfers child datasets
+  --skip-parent         Skipp the syncing of the parent dataset. Doesg nothing without '--recursive' option.
   --source-bwlimit=<limit k|m|g|t>  Bandwidth limit on the source transfer
   --target-bwlimit=<limit k|m|g|t>  Bandwidth limit on the target transfer
   --no-stream           Replicates using newest snapshot instead of intermediates

From 70b259ac3cb9ef9167776eac0424d0a78ea0c0c4 Mon Sep 17 00:00:00 2001
From: Christoph Klaffl <christoph@phreaker.eu>
Date: Tue, 19 Jun 2018 18:24:34 +0200
Subject: [PATCH 04/24] typos

---
 syncoid | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/syncoid b/syncoid
index 5cbc1c4..8ab3a41 100755
--- a/syncoid
+++ b/syncoid
@@ -1142,7 +1142,7 @@ Options:
 
   --compress=FORMAT     Compresses data during transfer. Currently accepted options are gzip, pigz-fast, pigz-slow, lzo (default) & none
   --recursive|r         Also transfers child datasets
-  --skip-parent         Skipp the syncing of the parent dataset. Doesg nothing without '--recursive' option.
+  --skip-parent         Skips syncing of the parent dataset. Does nothing without '--recursive' option.
   --source-bwlimit=<limit k|m|g|t>  Bandwidth limit on the source transfer
   --target-bwlimit=<limit k|m|g|t>  Bandwidth limit on the target transfer
   --no-stream           Replicates using newest snapshot instead of intermediates

From 0f8fee7637ec1265bd0a72011a08b0666e6123c4 Mon Sep 17 00:00:00 2001
From: Christoph Klaffl <christoph@phreaker.eu>
Date: Tue, 19 Jun 2018 19:43:36 +0200
Subject: [PATCH 05/24] added option for using extra identification in the
 snapshot name for replicating to multiple targets

---
 README.md |  4 ++++
 syncoid   | 18 +++++++++++++++---
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index cc75bdf..632a0af 100644
--- a/README.md
+++ b/README.md
@@ -122,6 +122,10 @@ As of 1.4.18, syncoid also automatically supports and enables resume of interrup
 
 	This is the destination dataset. It can be either local or remote.
 
++ --identifier=
+
+	Adds the given identifier to the snapshot name after "syncoid_" prefix and before the hostname. This enables the use case of reliable replication to multiple targets from the same host. The following chars are allowed: a-z, A-Z, 0-9 and -.
+
 + -r --recursive
 
 	This will also transfer child datasets.
diff --git a/syncoid b/syncoid
index 999ee79..dcb9e2f 100755
--- a/syncoid
+++ b/syncoid
@@ -19,7 +19,7 @@ use Sys::Hostname;
 my %args = ('sshkey' => '', 'sshport' => '', 'sshcipher' => '', 'sshoption' => [], 'target-bwlimit' => '', 'source-bwlimit' => '');
 GetOptions(\%args, "no-command-checks", "monitor-version", "compress=s", "dumpsnaps", "recursive|r",
                    "source-bwlimit=s", "target-bwlimit=s", "sshkey=s", "sshport=i", "sshcipher|c=s", "sshoption|o=s@",
-                   "debug", "quiet", "no-stream", "no-sync-snap", "no-resume") or pod2usage(2);
+                   "debug", "quiet", "no-stream", "no-sync-snap", "no-resume", "identifier=s") or pod2usage(2);
 
 my %compressargs = %{compressargset($args{'compress'} || 'default')}; # Can't be done with GetOptions arg, as default still needs to be set
 
@@ -71,6 +71,17 @@ if (length $args{'sshkey'}) {
 }
 my $sshoptions = join " ", map { "-o " . $_ } @{$args{'sshoption'}}; # deref required
 
+my $identifier = "";
+if (length $args{'identifier'}) {
+	if ($args{'identifier'} !~ /^[a-zA-Z0-9-]+$/) {
+		# invalid extra identifier
+		print("CRITICAL: extra identifier contains invalid chars!\n");
+		pod2usage(2);
+		exit 127;
+	}
+	$identifier = "$args{'identifier'}_";
+}
+
 # figure out if source and/or target are remote.
 $sshcmd = "$sshcmd $args{'sshcipher'} $sshoptions $args{'sshport'} $args{'sshkey'}";
 if ($debug) { print "DEBUG: SSHCMD: $sshcmd\n"; }
@@ -812,7 +823,7 @@ sub pruneoldsyncsnaps {
 
 	# only prune snaps beginning with syncoid and our own hostname
 	foreach my $snap(@snaps) {
-		if ($snap =~ /^syncoid_\Q$hostid\E/) {
+		if ($snap =~ /^syncoid_\Q$identifier$hostid\E/) {
 			# no matter what, we categorically refuse to
 			# prune the new sync snap we created for this run
 			if ($snap ne $newsyncsnap) {
@@ -898,7 +909,7 @@ sub newsyncsnap {
 	if ($isroot) { $mysudocmd = ''; } else { $mysudocmd = $sudocmd; }
 	my $hostid = hostname();
 	my %date = getdate();
-	my $snapname = "syncoid\_$hostid\_$date{'stamp'}";
+	my $snapname = "syncoid\_$identifier$hostid\_$date{'stamp'}";
 	my $snapcmd = "$rhost $mysudocmd $zfscmd snapshot $fsescaped\@$snapname\n";
 	system($snapcmd) == 0
 		or die "CRITICAL ERROR: $snapcmd failed: $?";
@@ -1136,6 +1147,7 @@ syncoid - ZFS snapshot replication tool
 Options:
 
   --compress=FORMAT     Compresses data during transfer. Currently accepted options are gzip, pigz-fast, pigz-slow, lzo (default) & none
+  --identifier=EXTRA    Extra identifier which is included in the snapshot name. Can be used for replicating to multiple targets.
   --recursive|r         Also transfers child datasets
   --source-bwlimit=<limit k|m|g|t>  Bandwidth limit on the source transfer
   --target-bwlimit=<limit k|m|g|t>  Bandwidth limit on the target transfer

From ba3836ec520efc30689238e294de1d1c2026fc1b Mon Sep 17 00:00:00 2001
From: Christoph Klaffl <christoph@phreaker.eu>
Date: Fri, 6 Jul 2018 15:52:54 +0200
Subject: [PATCH 06/24] fixed monitor-health command for pools containing cache
 and log devices

---
 sanoid | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/sanoid b/sanoid
index 9cd9d33..485ee08 100755
--- a/sanoid
+++ b/sanoid
@@ -976,6 +976,11 @@ sub check_zpool() {
 			## other cases
 			my ($dev, $sta) = /^\s+(\S+)\s+(\S+)/;
 
+			if (!defined($sta)) {
+				# cache and logs are special and don't have a status
+				next;
+			}
+
 			## pool online, not degraded thanks to dead/corrupted disk
 			if ($state eq "OK" && $sta eq "UNAVAIL") {
 				$state="WARNING";
@@ -1111,7 +1116,7 @@ sub checklock {
 	# make sure lockfile contains something
 	if ( -z $lockfile) {
 	        # zero size lockfile, something is wrong
-	        die "ERROR: something is wrong! $lockfile is empty\n"; 
+	        die "ERROR: something is wrong! $lockfile is empty\n";
 	}
 
 	# lockfile exists. read pid and mutex from it. see if it's our pid.  if not, see if

From f9c1cbb74a3c07fc9e0368721cdcedcc0b2b4a0f Mon Sep 17 00:00:00 2001
From: Jim Salter <github@jrs-s.net>
Date: Sat, 7 Jul 2018 12:06:35 -0400
Subject: [PATCH 07/24] Update INSTALL

---
 INSTALL | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/INSTALL b/INSTALL
index 33b510d..f0de17b 100644
--- a/INSTALL
+++ b/INSTALL
@@ -8,7 +8,7 @@ default for SSH transport since v1.4.6. Syncoid runs will fail if one of them
 is not available on either end of the transport.
 
 On Ubuntu: apt install pv lzop mbuffer
-On CentOS: yum install lzo pv mbuffer lzop
+On CentOS: yum install lzo pv mbuffer lzop perl-Data-Dumper
 On FreeBSD: pkg install pv mbuffer lzop
 
 FreeBSD notes: FreeBSD may place pv and lzop in somewhere other than

From dc0afebb30865faa16f42c496b2c59e5ed72b690 Mon Sep 17 00:00:00 2001
From: Christoph Klaffl <christoph@phreaker.eu>
Date: Sat, 7 Jul 2018 20:06:17 +0200
Subject: [PATCH 08/24] allow extra identifier to contain all characters for
 snapshots names which are allowed by zfs

---
 syncoid | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/syncoid b/syncoid
index d25d9de..aaf5490 100755
--- a/syncoid
+++ b/syncoid
@@ -73,7 +73,7 @@ my $sshoptions = join " ", map { "-o " . $_ } @{$args{'sshoption'}}; # deref req
 
 my $identifier = "";
 if (length $args{'identifier'}) {
-	if ($args{'identifier'} !~ /^[a-zA-Z0-9-]+$/) {
+	if ($args{'identifier'} !~ /^[a-zA-Z0-9-_:.]+$/) {
 		# invalid extra identifier
 		print("CRITICAL: extra identifier contains invalid chars!\n");
 		pod2usage(2);

From f409b955694b9dc5f403f16593cc6540cac7fe67 Mon Sep 17 00:00:00 2001
From: Christoph Klaffl <christoph@phreaker.eu>
Date: Sat, 7 Jul 2018 20:10:02 +0200
Subject: [PATCH 09/24] updated parameter documention of --identifier regarding
 allowed characters

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 4e1f651..e359886 100644
--- a/README.md
+++ b/README.md
@@ -130,7 +130,7 @@ As of 1.4.18, syncoid also automatically supports and enables resume of interrup
 
 + --identifier=
 
-	Adds the given identifier to the snapshot name after "syncoid_" prefix and before the hostname. This enables the use case of reliable replication to multiple targets from the same host. The following chars are allowed: a-z, A-Z, 0-9 and -.
+	Adds the given identifier to the snapshot name after "syncoid_" prefix and before the hostname. This enables the use case of reliable replication to multiple targets from the same host. The following chars are allowed: a-z, A-Z, 0-9, _, -, : and . .
 
 + -r --recursive
 

From 75d8174e6997286aad57d03d1c6ad86d2fd89c79 Mon Sep 17 00:00:00 2001
From: Piotr Paczynski <ppaczyn@gmail.com>
Date: Wed, 18 Jul 2018 01:19:37 +0200
Subject: [PATCH 10/24] Fix 'resume support' detection on FreeBSD

---
 syncoid | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/syncoid b/syncoid
index aaf5490..31ff757 100755
--- a/syncoid
+++ b/syncoid
@@ -614,7 +614,7 @@ sub checkcommands {
 
 	# check for ZFS resume feature support
 	if ($resume) {
-		my $resumechkcmd = "$zfscmd get receive_resume_token -d 0";
+		my $resumechkcmd = "$zfscmd get -d 0 receive_resume_token";
 
 		if ($debug) { print "DEBUG: checking availability of zfs resume feature on source...\n"; }
 		$avail{'sourceresume'} = system("$sourcessh $resumechkcmd >/dev/null 2>&1");

From f5508a240387bb80f3db6937c8724fa006e4a5b2 Mon Sep 17 00:00:00 2001
From: Christoph Klaffl <christoph@phreaker.eu>
Date: Thu, 26 Jul 2018 21:46:50 +0200
Subject: [PATCH 11/24] fix typo to make local source bwlimit work

---
 syncoid | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/syncoid b/syncoid
index f53aee4..cf941bf 100755
--- a/syncoid
+++ b/syncoid
@@ -757,7 +757,7 @@ sub buildsynccmd {
 		$synccmd = "$sendcmd |";
 		# avoid confusion - accept either source-bwlimit or target-bwlimit as the bandwidth limiting option here
 		my $bwlimit = '';
-		if (length $args{'bwlimit'}) {
+		if (length $args{'source-bwlimit'}) {
 			$bwlimit = $args{'source-bwlimit'};
 		} elsif (length $args{'target-bwlimit'}) {
 			$bwlimit = $args{'target-bwlimit'};

From e85c375bbea636aa068bb3cd4add7d621568784c Mon Sep 17 00:00:00 2001
From: Christoph Klaffl <christoph@phreaker.eu>
Date: Thu, 26 Jul 2018 21:53:56 +0200
Subject: [PATCH 12/24] fixed typo

---
 syncoid | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/syncoid b/syncoid
index f53aee4..8be70e5 100755
--- a/syncoid
+++ b/syncoid
@@ -863,7 +863,7 @@ sub pruneoldsyncsnaps {
 				$prunecmd = escapeshellparam($prunecmd);
 			}
 			system("$rhost $prunecmd") == 0
-				or warn "CRITICAL ERROR: $rhost $prunecmd failed: $?";
+				or warn "WARNING: $rhost $prunecmd failed: $?";
 			$prunecmd = '';
 			$counter = 0;
 		}

From 7c68ef5e8f2f491fe7de3b23a53f8b64a026a883 Mon Sep 17 00:00:00 2001
From: Christoph Klaffl <christoph@phreaker.eu>
Date: Sun, 29 Jul 2018 13:16:53 +0200
Subject: [PATCH 13/24] return a non zero exit code if there was a problem
 replicating datasets

---
 syncoid | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/syncoid b/syncoid
index 6c569b2..6453d0f 100755
--- a/syncoid
+++ b/syncoid
@@ -97,6 +97,7 @@ my $targetsudocmd = $targetisroot ? '' : $sudocmd;
 my %avail = checkcommands();
 
 my %snaps;
+my $exitcode = 0;
 
 ## break here to call replication individually so that we ##
 ## can loop across children separately, for recursive     ##
@@ -127,7 +128,7 @@ if ($targethost ne '') {
 	close FH;
 }
 
-exit 0;
+exit $exitcode;
 
 ##############################################################################
 ##############################################################################
@@ -186,6 +187,7 @@ sub syncdataset {
 	# make sure target is not currently in receive.
 	if (iszfsbusy($targethost,$targetfs,$targetisroot)) {
 		warn "Cannot sync now: $targetfs is already target of a zfs receive process.\n";
+		if ($exitcode < 1) { $exitcode = 1; }
 		return 0;
 	}
 
@@ -236,6 +238,7 @@ sub syncdataset {
 			$newsyncsnap = getnewestsnapshot($sourcehost,$sourcefs,$sourceisroot);
 			if ($newsyncsnap eq 0) {
 				warn "CRITICAL: no snapshots exist on source $sourcefs, and you asked for --no-sync-snap.\n";
+				if ($exitcode < 1) { $exitcode = 1; }
 				return 0;
 			}
 		}
@@ -292,6 +295,7 @@ sub syncdataset {
 		# make sure target is (still) not currently in receive.
 		if (iszfsbusy($targethost,$targetfs,$targetisroot)) {
 			warn "Cannot sync now: $targetfs is already target of a zfs receive process.\n";
+			if ($exitcode < 1) { $exitcode = 1; }
 			return 0;
 		}
 		system($synccmd) == 0
@@ -318,6 +322,7 @@ sub syncdataset {
 			# make sure target is (still) not currently in receive.
 			if (iszfsbusy($targethost,$targetfs,$targetisroot)) {
 				warn "Cannot sync now: $targetfs is already target of a zfs receive process.\n";
+				if ($exitcode < 1) { $exitcode = 1; }
 				return 0;
 			}
 
@@ -325,9 +330,12 @@ sub syncdataset {
 			if ($debug) { print "DEBUG: $synccmd\n"; }
 
 			if ($oldestsnap ne $newsyncsnap) {
-				system($synccmd) == 0
-					or warn "CRITICAL ERROR: $synccmd failed: $?";
+				my $ret = system($synccmd);
+				if ($ret != 0) {
+					warn "CRITICAL ERROR: $synccmd failed: $?";
+					if ($exitcode < 1) { $exitcode = 1; }
 					return 0;
+				}
 			} else {
 				if (!$quiet) { print "INFO: no incremental sync needed; $oldestsnap is already the newest available snapshot.\n"; }
 			}
@@ -380,6 +388,7 @@ sub syncdataset {
 		# make sure target is (still) not currently in receive.
 		if (iszfsbusy($targethost,$targetfs,$targetisroot)) {
 			warn "Cannot sync now: $targetfs is already target of a zfs receive process.\n";
+			if ($exitcode < 1) { $exitcode = 1; }
 			return 0;
 		}
 
@@ -910,6 +919,7 @@ sub getmatchingsnapshot {
 	}
 
 	# if we got this far, we failed to find a matching snapshot.
+	if ($exitcode < 2) { $exitcode = 2; }
 
 	print "\n";
 	print "CRITICAL ERROR: Target $targetfs exists but has no snapshots matching with $sourcefs!\n";

From 63eec4994c20d7eb6207f6c6927badf138442f22 Mon Sep 17 00:00:00 2001
From: Christoph Klaffl <christoph@phreaker.eu>
Date: Mon, 30 Jul 2018 22:21:14 +0200
Subject: [PATCH 14/24] don't die on some critical sync errors, but continue to
 replicate all the other datasets. after all is done exit with an error code

---
 syncoid | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/syncoid b/syncoid
index 6453d0f..1ef1506 100755
--- a/syncoid
+++ b/syncoid
@@ -298,8 +298,11 @@ sub syncdataset {
 			if ($exitcode < 1) { $exitcode = 1; }
 			return 0;
 		}
-		system($synccmd) == 0
-			or die "CRITICAL ERROR: $synccmd failed: $?";
+		system($synccmd) == 0 or do {
+			warn "CRITICAL ERROR: $synccmd failed: $?";
+			if ($exitcode < 2) { $exitcode = 2; }
+			return 0;
+		};
 
 		# now do an -I to the new sync snapshot, assuming there were any snapshots
 		# other than the new sync snapshot to begin with, of course - and that we
@@ -359,8 +362,11 @@ sub syncdataset {
 
 		    if (!$quiet) { print "Resuming interrupted zfs send/receive from $sourcefs to $targetfs (~ $disp_pvsize remaining):\n"; }
 		    if ($debug) { print "DEBUG: $synccmd\n"; }
-		    system("$synccmd") == 0
-		        or die "CRITICAL ERROR: $synccmd failed: $?";
+		    system("$synccmd") == 0 or do {
+		        warn "CRITICAL ERROR: $synccmd failed: $?";
+		        if ($exitcode < 2) { $exitcode = 2; }
+		        return 0;
+		    };
 
 		    # a resumed transfer will only be done to the next snapshot,
 		    # so do an normal sync cycle
@@ -416,8 +422,11 @@ sub syncdataset {
 
 			if (!$quiet) { print "Sending incremental $sourcefs\@$matchingsnap ... $newsyncsnap (~ $disp_pvsize):\n"; }
 			if ($debug) { print "DEBUG: $synccmd\n"; }
-			system("$synccmd") == 0
-				or die "CRITICAL ERROR: $synccmd failed: $?";
+			system("$synccmd") == 0 or do {
+				warn "CRITICAL ERROR: $synccmd failed: $?";
+				if ($exitcode < 2) { $exitcode = 2; }
+				return 0;
+			};
 
 			# restore original readonly value to target after sync complete
 				# dyking this functionality out for the time being due to buggy mount/unmount behavior

From 9668567a870def5418032fb922d3a27a643059fa Mon Sep 17 00:00:00 2001
From: Christoph Klaffl <christoph@phreaker.eu>
Date: Mon, 30 Jul 2018 22:53:48 +0200
Subject: [PATCH 15/24] continue replication on more critical errors

---
 syncoid | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/syncoid b/syncoid
index 1ef1506..73205ce 100755
--- a/syncoid
+++ b/syncoid
@@ -233,6 +233,10 @@ sub syncdataset {
 		if (!defined $args{'no-sync-snap'}) {
 			# create a new syncoid snapshot on the source filesystem.
 			$newsyncsnap = newsyncsnap($sourcehost,$sourcefs,$sourceisroot);
+			if (!$newsyncsnap) {
+				# we already whined about the error
+				return 0;
+			}
 		} else {
 			# we don't want sync snapshots created, so use the newest snapshot we can find.
 			$newsyncsnap = getnewestsnapshot($sourcehost,$sourcefs,$sourceisroot);
@@ -267,6 +271,11 @@ sub syncdataset {
 		}
 		my $oldestsnap = getoldestsnapshot(\%snaps);
 		if (! $oldestsnap) {
+			if (defined ($args{'no-sync-snap'}) ) {
+				# we already whined about the missing snapshots
+				return 0;
+			}
+
 			# getoldestsnapshot() returned false, so use new sync snapshot
 			if ($debug) { print "DEBUG: getoldestsnapshot() returned false, so using $newsyncsnap.\n"; }
 			$oldestsnap = $newsyncsnap;
@@ -752,7 +761,7 @@ sub getoldestsnapshot {
 	# must not have had any snapshots on source - luckily, we already made one, amirite?
 	if (defined ($args{'no-sync-snap'}) ) {
 		# well, actually we set --no-sync-snap, so no we *didn't* already make one. Whoops.
-		die "CRIT: --no-sync-snap is set, and getoldestsnapshot() could not find any snapshots on source!\n";
+		warn "CRIT: --no-sync-snap is set, and getoldestsnapshot() could not find any snapshots on source!\n";
 	}
 	return 0;
 }
@@ -774,6 +783,7 @@ sub getnewestsnapshot {
 		#        we also probably need an argument to mute this WARN, for people who deliberately exclude
 		#        datasets from recursive replication this way.
 		warn "WARN: --no-sync-snap is set, and getnewestsnapshot() could not find any snapshots on source for current dataset. Continuing.\n";
+		if ($exitcode < 2) { $exitcode = 2; }
 	}
 	return 0;
 }
@@ -961,8 +971,12 @@ sub newsyncsnap {
 	my %date = getdate();
 	my $snapname = "syncoid\_$identifier$hostid\_$date{'stamp'}";
 	my $snapcmd = "$rhost $mysudocmd $zfscmd snapshot $fsescaped\@$snapname\n";
-	system($snapcmd) == 0
-		or die "CRITICAL ERROR: $snapcmd failed: $?";
+	system($snapcmd) == 0 or do {
+		warn "CRITICAL ERROR: $snapcmd failed: $?";
+		if ($exitcode < 2) { $exitcode = 2; }
+		return 0;
+	};
+
 	return $snapname;
 }
 

From fb8edad885522040369c6ab95edfbb922fb6901d Mon Sep 17 00:00:00 2001
From: Attie Grande <attie@attie.co.uk>
Date: Fri, 3 Aug 2018 09:13:35 +0100
Subject: [PATCH 16/24] compression warnings are no longer hidden by --quiet

---
 syncoid | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/syncoid b/syncoid
index aec99cd..85d5e16 100755
--- a/syncoid
+++ b/syncoid
@@ -452,13 +452,13 @@ sub checkcommands {
 
 	if ($avail{'sourcecompress'} eq '') {
 		if ($compressargs{'rawcmd'} ne '') {
-			if (!$quiet) { print "WARN: $compressargs{'rawcmd'} not available on source $s- sync will continue without compression.\n"; }
+			print "WARN: $compressargs{'rawcmd'} not available on source $s- sync will continue without compression.\n";
 		}
 		$avail{'compress'} = 0;
 	}
 	if ($avail{'targetcompress'} eq '') {
 		if ($compressargs{'rawcmd'} ne '') {
-			if (!$quiet) { print "WARN: $compressargs{'rawcmd'} not available on target $t - sync will continue without compression.\n"; }
+			print "WARN: $compressargs{'rawcmd'} not available on target $t - sync will continue without compression.\n";
 		}
 		$avail{'compress'} = 0;
 	}
@@ -471,7 +471,7 @@ sub checkcommands {
 	# corner case - if source AND target are BOTH remote, we have to check for local compress too
 	if ($sourcehost ne '' && $targethost ne '' && $avail{'localcompress'} eq '') {
 		if ($compressargs{'rawcmd'} ne '') {
-			if (!$quiet) { print "WARN: $compressargs{'rawcmd'} not available on local machine - sync will continue without compression.\n"; }
+			print "WARN: $compressargs{'rawcmd'} not available on local machine - sync will continue without compression.\n";
 		}
 		$avail{'compress'} = 0;
 	}

From 39d1fd38c1edd52f45b44707beabe32e3a20900d Mon Sep 17 00:00:00 2001
From: Attie Grande <attie@attie.co.uk>
Date: Fri, 5 Jan 2018 21:54:06 +0000
Subject: [PATCH 17/24] added ability to skip datasets... simply set
 syncoid:no-sync=true

---
 syncoid | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/syncoid b/syncoid
index 6c569b2..8adaa87 100755
--- a/syncoid
+++ b/syncoid
@@ -183,6 +183,11 @@ sub syncdataset {
 
 	if ($debug) { print "DEBUG: syncing source $sourcefs to target $targetfs.\n"; }
 
+	if (getzfsvalue($sourcehost,$sourcefs,$sourceisroot,'syncoid:no-sync') eq 'true') {
+		print "Skipping dataset (syncoid:nosync=true): $sourcefs...\n";
+		return 0;
+	}
+
 	# make sure target is not currently in receive.
 	if (iszfsbusy($targethost,$targetfs,$targetisroot)) {
 		warn "Cannot sync now: $targetfs is already target of a zfs receive process.\n";

From 22c137627a9a923807565dff01794d9d3775e767 Mon Sep 17 00:00:00 2001
From: Attie Grande <attie@attie.co.uk>
Date: Sat, 6 Jan 2018 10:15:30 +0000
Subject: [PATCH 18/24] updated doc for syncoid:no-sync

---
 README.md | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/README.md b/README.md
index e359886..ba325e6 100644
--- a/README.md
+++ b/README.md
@@ -118,6 +118,14 @@ If ZFS supports resumeable send/receive streams on both the source and target th
 
 As of 1.4.18, syncoid also automatically supports and enables resume of interrupted replication when both source and target support this feature.
 
+##### Syncoid Dataset Properties
+
++ syncoid:no-sync
+
+  Setting this to `true` will prevent the dataset from being handled by syncoid in _any_ way - it will be skipped. This can be useful for preventing certain datasets from being transferred when recursively handling a tree.
+
+  Note that this will also prevent syncoid from handling the dataset if given explicitly on the command line.
+
 ##### Syncoid Command Line Options
 
 + [source]

From b02b9a582bd3f92c01f16c954add64a78e647896 Mon Sep 17 00:00:00 2001
From: Attie Grande <attie@attie.co.uk>
Date: Sat, 6 Jan 2018 10:43:30 +0000
Subject: [PATCH 19/24] now obeying --quiet, and added 'INFO: ' prefix to skip
 message

---
 syncoid | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/syncoid b/syncoid
index 8adaa87..2201f41 100755
--- a/syncoid
+++ b/syncoid
@@ -184,7 +184,7 @@ sub syncdataset {
 	if ($debug) { print "DEBUG: syncing source $sourcefs to target $targetfs.\n"; }
 
 	if (getzfsvalue($sourcehost,$sourcefs,$sourceisroot,'syncoid:no-sync') eq 'true') {
-		print "Skipping dataset (syncoid:nosync=true): $sourcefs...\n";
+		if (!$quiet) { print "INFO: Skipping dataset (syncoid:nosync=true): $sourcefs...\n"; }
 		return 0;
 	}
 

From c188e47a6da2d8ee2857a8eb1c0400bc78fc7a53 Mon Sep 17 00:00:00 2001
From: Attie Grande <attie@attie.co.uk>
Date: Fri, 9 Mar 2018 15:15:06 +0000
Subject: [PATCH 20/24] inverted sync/no-sync logic

---
 syncoid | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/syncoid b/syncoid
index 2201f41..20c0853 100755
--- a/syncoid
+++ b/syncoid
@@ -183,8 +183,8 @@ sub syncdataset {
 
 	if ($debug) { print "DEBUG: syncing source $sourcefs to target $targetfs.\n"; }
 
-	if (getzfsvalue($sourcehost,$sourcefs,$sourceisroot,'syncoid:no-sync') eq 'true') {
-		if (!$quiet) { print "INFO: Skipping dataset (syncoid:nosync=true): $sourcefs...\n"; }
+	if (getzfsvalue($sourcehost,$sourcefs,$sourceisroot,'syncoid:sync') eq 'false') {
+		if (!$quiet) { print "INFO: Skipping dataset (syncoid:sync=false): $sourcefs...\n"; }
 		return 0;
 	}
 

From f0a37310a54b5e421264d05a02ad226a1409bb98 Mon Sep 17 00:00:00 2001
From: Attie Grande <attie@attie.co.uk>
Date: Fri, 9 Mar 2018 15:18:03 +0000
Subject: [PATCH 21/24] implemented sync true/false/${HOSTS} filtering

---
 syncoid | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/syncoid b/syncoid
index 20c0853..7877723 100755
--- a/syncoid
+++ b/syncoid
@@ -183,9 +183,20 @@ sub syncdataset {
 
 	if ($debug) { print "DEBUG: syncing source $sourcefs to target $targetfs.\n"; }
 
-	if (getzfsvalue($sourcehost,$sourcefs,$sourceisroot,'syncoid:sync') eq 'false') {
+	my $sync = getzfsvalue($sourcehost,$sourcefs,$sourceisroot,'syncoid:sync');
+
+	if ($sync eq 'true' || $sync eq '-') {
+		# definitely sync this dataset - if a host is called 'true' or '-', then you're special
+	} elsif ($sync eq 'false') {
 		if (!$quiet) { print "INFO: Skipping dataset (syncoid:sync=false): $sourcefs...\n"; }
 		return 0;
+	} else {
+		my $hostid = hostname();
+		my @hosts = split(/,/,$sync);
+		if (!(grep $hostid eq $_, @hosts)) {
+			if (!$quiet) { print "INFO: Skipping dataset (syncoid:sync doesn't include $hostid): $sourcefs...\n"; }
+			return 0;
+		}
 	}
 
 	# make sure target is not currently in receive.

From a4e490f430b73454422c28254012a3328f9bbe98 Mon Sep 17 00:00:00 2001
From: Attie Grande <attie@attie.co.uk>
Date: Fri, 9 Mar 2018 15:28:39 +0000
Subject: [PATCH 22/24] updated documentation for the syncoid:sync property's
 new behaviour

---
 README.md | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index ba325e6..bb6ec89 100644
--- a/README.md
+++ b/README.md
@@ -120,11 +120,27 @@ As of 1.4.18, syncoid also automatically supports and enables resume of interrup
 
 ##### Syncoid Dataset Properties
 
-+ syncoid:no-sync
++ syncoid:sync
 
-  Setting this to `true` will prevent the dataset from being handled by syncoid in _any_ way - it will be skipped. This can be useful for preventing certain datasets from being transferred when recursively handling a tree.
+  Available values:
 
-  Note that this will also prevent syncoid from handling the dataset if given explicitly on the command line.
+  + `true` (default if unset)
+
+    This dataset will be synchronised to all hosts.
+
+  + `false`
+
+    This dataset will not be synchronised to any hosts - it will be skipped. This can be useful for preventing certain datasets from being transferred when recursively handling a tree.
+
+  + `host1,host2,...`
+
+    A comma seperated list of hosts. This dataset will only be synchronised by hosts listed in the property.
+
+    _Note_: this check is performed by the host running `syncoid`, thus the local hostname must be present for inclusion during a push operation // the remote hostname must be present for a pull.
+
+  _Note_: this will also prevent syncoid from handling the dataset if given explicitly on the command line.
+
+  _Note_: syncing a child of a no-sync dataset will currently result in a critical error
 
 ##### Syncoid Command Line Options
 

From 60b2dedc456a8464f86cf75dacfe62c0b6410dbc Mon Sep 17 00:00:00 2001
From: Attie Grande <attie@attie.co.uk>
Date: Mon, 6 Aug 2018 14:07:58 +0100
Subject: [PATCH 23/24] fixed typo

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index bb6ec89..8c05fb3 100644
--- a/README.md
+++ b/README.md
@@ -134,7 +134,7 @@ As of 1.4.18, syncoid also automatically supports and enables resume of interrup
 
   + `host1,host2,...`
 
-    A comma seperated list of hosts. This dataset will only be synchronised by hosts listed in the property.
+    A comma separated list of hosts. This dataset will only be synchronised by hosts listed in the property.
 
     _Note_: this check is performed by the host running `syncoid`, thus the local hostname must be present for inclusion during a push operation // the remote hostname must be present for a pull.
 

From d0ba0bc284bb92a8f0e63cfbd773e8c61e175973 Mon Sep 17 00:00:00 2001
From: Attie Grande <attie@attie.co.uk>
Date: Mon, 6 Aug 2018 14:16:25 +0100
Subject: [PATCH 24/24] handled empty syncoid:sync property - behaves like
 unset

---
 README.md | 4 +++-
 syncoid   | 3 ++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 8c05fb3..b833dec 100644
--- a/README.md
+++ b/README.md
@@ -140,7 +140,9 @@ As of 1.4.18, syncoid also automatically supports and enables resume of interrup
 
   _Note_: this will also prevent syncoid from handling the dataset if given explicitly on the command line.
 
-  _Note_: syncing a child of a no-sync dataset will currently result in a critical error
+  _Note_: syncing a child of a no-sync dataset will currently result in a critical error.
+
+  _Note_: empty properties will be handled as if they were unset.
 
 ##### Syncoid Command Line Options
 
diff --git a/syncoid b/syncoid
index 7877723..fa00751 100755
--- a/syncoid
+++ b/syncoid
@@ -185,7 +185,8 @@ sub syncdataset {
 
 	my $sync = getzfsvalue($sourcehost,$sourcefs,$sourceisroot,'syncoid:sync');
 
-	if ($sync eq 'true' || $sync eq '-') {
+	if ($sync eq 'true' || $sync eq '-' || $sync eq '') {
+		# empty is handled the same as unset (aka: '-')
 		# definitely sync this dataset - if a host is called 'true' or '-', then you're special
 	} elsif ($sync eq 'false') {
 		if (!$quiet) { print "INFO: Skipping dataset (syncoid:sync=false): $sourcefs...\n"; }