Fail on missing clone

README.md

@@ -344,6 +344,18 @@ As of 1.4.18, syncoid also automatically supports and enables resume of interrup
 
 	This argument tells syncoid to not recreate clones on the target on initial sync, and do a normal replication instead.
 
++ --no-full-clone
+	Only applies to recursive transfer when clone handling is active.
+	In case a clone origin is missing (on destination) because its transfer was interrupted                                        
+    don't switch to a full clone sync.                                                                    
+    Example worst case scenario this may help prevent:                                                                                  
+    A 1TB dataset has 500 identical clones. Overall it uses just 1 TB storage space at the source, because
+	all clone share the storage with origin.                              
+    Assume a recursive transfer is started that needs to send all datasets (origin and 500 clones). 
+	Assume also the origin dataset transfer ends up failing. Without selecting this option, the recursive 
+	transfer proceeds to next recursive dataset, and because origin is missing (receive not completed), 
+	each clone becomes a full clone and we end up trying to transfer 500TB !
+
 + --dumpsnaps
 
 	This prints a list of snapshots during the run.

syncoid

@@ -25,7 +25,7 @@ GetOptions(\%args, "no-command-checks", "monitor-version", "compress=s", "dumpsn
                    "source-bwlimit=s", "target-bwlimit=s", "sshconfig=s", "sshkey=s", "sshport=i", "sshcipher|c=s", "sshoption|o=s@",
                    "debug", "quiet", "no-stream", "no-sync-snap", "no-resume", "exclude=s@", "skip-parent", "identifier=s",
                    "no-clone-handling", "no-privilege-elevation", "force-delete", "no-rollback", "create-bookmark",
-                   "pv-options=s" => \$pvoptions, "keep-sync-snap", "preserve-recordsize", "mbuffer-size=s" => \$mbuffer_size) 
+                   "pv-options=s" => \$pvoptions, "keep-sync-snap", "preserve-recordsize", "mbuffer-size=s" => \$mbuffer_size, "no-full-clone") 
                    or pod2usage(2);
 
 my %compressargs = %{compressargset($args{'compress'} || 'default')}; # Can't be done with GetOptions arg, as default still needs to be set
@@ -183,6 +183,10 @@ if (!defined $args{'recursive'}) {
 			}
 
 			if ($found == 0) {
+				if (defined $args{'no-full-clone'}) {
+					print("SKIPPING: $dataset because origin clone is missing. Retry running syncoid.\n");
+					next;
+				}
 				# clone source is not replicated, do a full replication
 				$origin = undef;
 			} else {
@@ -491,8 +495,13 @@ sub syncdataset {
 		system($synccmd) == 0 or do {
 			if (defined $origin) {
 				print "INFO: clone creation failed, trying ordinary replication as fallback\n";
-				syncdataset($sourcehost, $sourcefs, $targethost, $targetfs, undef, 1);
-				return 0;
+				if (defined $args{'no-full-clone'}) {                  
+					print("SKIPPING: $synccmd because origin clone is missing. Retry running syncoid.\n");
+					# Fall through to normal error                                                                                  
+				} else {
+					syncdataset($sourcehost, $sourcefs, $targethost, $targetfs, undef, 1);
+					return 0;
+				}
 			}
 
 			warn "CRITICAL ERROR: $synccmd failed: $?";
@@ -2018,5 +2027,6 @@ Options:
   --no-resume           Don't use the ZFS resume feature if available
   --no-clone-handling   Don't try to recreate clones on target
   --no-privilege-elevation  Bypass the root check, for use with ZFS permission delegation
+  --no-full-clone       Don't convert a clone into a full clone if the clone's origin is missing at destination 
 
   --force-delete        Remove target datasets recursively, if there are no matching snapshots/bookmarks (also overwrites conflicting named snapshots)