+ grep ^${backup_pool}/${remote_fs}@ |
+ grep -v ^${backup_pool}/${current_backup_marker} |
+ awk "{gsub(/^$backup_pool./,\"\",\$1); print\$1}" > $local_list
+# If no local snapshots exist, we may need to send the entire filesystem, which we'll do later
+# So, no error check here as a non-zero return code means the local filesystem or snaps are missing
+# We'll catch this later on as a case where we need to send the entire filesystem
+
+# Destroy the current backup marker snapshot on the remote system if it exists
+grep -q ${current_backup_marker} $remote_list
+if [ $? == 0 ]; then
+ $ssh $remote $zfs destroy ${current_backup_marker}
+ if [ $? != 0 ]; then
+ fatal_and_exit "-E- remote $zfs destroy $current_backup_marker on $hostname command failed" $mailto
+ fi
+fi
+
+# Create the current backup marker snapshot on the remote system
+$ssh $remote $zfs snapshot ${current_backup_marker}
+if [ $? != 0 ]; then
+ fatal_and_exit "-E- remote $zfs snapshot $current_backup_marker on $hostname command failed" $mailto
+fi
+
+# Check to see if the previous backup marker exists in the remote snapshot list.
+# Check to see if the previous backup marker exists in the local snapshot list.
+# If the previous backup markers exists, perform an incremental replicate. Else:
+# 1) check to see if a common snapshot exists, and perform an incremental replicate.
+# 2) if no common snapshot exists, destroy the local filesystem, and perform a full replicate.
+grep -q ${previous_backup_marker} $remote_list
+no_markers=$?
+grep -q ${previous_backup_marker} $local_list
+no_markers=$(($no_markers || $?))
+
+if [ $no_markers == 0 ]; then
+ # We found backup markers, incrementally send the new snaps
+
+ # First, rollback the local backup pool to the previous backup marker in case the previous
+ # backup was interrupted for some reason. If we don't do this, the zfs send -R command
+ # below may complain about snaps already existing as it tries to resend from the
+ # previous backup marker again from a previously interrupted replicate.
+ $zfs rollback -rf ${backup_pool}/${previous_backup_marker}
+ if [ $? != 0 ]; then
+ sleep 120
+ $zfs rollback -rf ${backup_pool}/${previous_backup_marker}
+ if [ $? != 0 ]; then
+ fatal_and_exit "-E- remote incremental $zfs rollback $backup_pool/$previous_backup_marker command failed on $hostname" $mailto
+ fi
+ fi
+ # Now it should be safe to send the snaps
+ replicate "$zfs send -Rc -I${previous_backup_marker} ${current_backup_marker}"
+ if [ $? != 0 ]; then
+ fatal_and_exit "-E- remote incremental $zfs send $previous_backup_marker command failed on $hostname" $mailto
+ fi
+else
+ # We didn't find any backup markers, next check to see if we have a common snapshot.