mode of operation is now a job parameter [closes #5]

zfs-backup.cfg

@@ -1,14 +1,17 @@
 # required format:
-# SOURCE	TARGET					KEEPDAYS	ENABLED
-# dataset	[user@host:]dataset			number		Y or N
+# SOURCE	TARGET					KEEPDAYS	MODE		ENABLED
+# dataset	[user@host:]dataset			number		backup or sync	Y or N
 
 # we are securing this elsewhere; if we are using this method, we'll need to configure the target host
 # 'user' needs an authorized and restricted public key for SSH access and sudoer rights on 'remotehost' to execute the following as root:
 # /usr/sbin/zfs recv -Feuv datapool/backup, /usr/sbin/zfs destroy -r datapool/backup/*
-data/home	user@remotehost:datapool/backup		7		Y
+data/home	user@remotehost:datapool/backup		7		backup		Y
 
 # this goes to another pool on this host so no further configuration is	necessary
-data/config	backup/data				5		Y
+data/config	backup/data				5		backup		Y
 
 # we no longer back this up
-data/volatile	backup/data				2		N
+data/volatile	backup/data				2		backup		N
+
+# we only sync this one
+data/replica	remote/dump				31		sync		Y

zfs-backup.sh

@@ -76,6 +76,8 @@ function backup() {
 	R_SNAPSHOTS=( $(${R_RMOD} zfs list -rt snapshot -d1 -Ho name -S creation ${SAVETO}/$( basename ${DATASET}) 2>/dev/null) )
 	check_dataset ${SAVETO}/$( basename ${DATASET}) && R_USED_BEFORE=$(snapuse ${SAVETO}/$( basename ${DATASET}))
 
+	if [ $MODE == "backup" ]
+		then
 			# determine current timestamp
 			DATE=$(date +%Y-%m-%d-%H%M)
 
@@ -84,6 +86,7 @@ function backup() {
 
 			# take a snapshot
 			zfs snapshot -r ${NEWSNAP}
+	fi
 	
 	# check if source is encrypted
 	if [ $ENCRYPTION_FEATURE != "disabled" ]
@@ -107,22 +110,32 @@ function backup() {
 											if [ ${#R_SNAPSHOTS[*]} -ge 1 ]
 												then
 													# remote snapshot(s) found
-																		R_SNAPMODIFIER="I $(dirname ${DATASET})/$(basename ${R_SNAPSHOTS[*]:(-1)})"
+													R_SNAPMODIFIER="I $(dirname ${DATASET})/$(basename ${R_SNAPSHOTS[0]})"
 											fi
 											# send any previous snapshots
 											zfs send -Rcv${RAW_MOD}${R_SNAPMODIFIER} ${LASTSNAP} | ${RMOD:-$R_RMOD} zfs recv -Feu${RESUME_MOD}v ${SAVETO} 2>&1 >> ${LOGFILE}
+											if [[ ${PIPESTATUS[*]} =~ [1-9]+ ]]
+												then
+													# replication failure
+													logger -t $(basename ${0%.sh}) -p user.notice "failed to replicate ${LASTSNAP} to ${TARGET:-local}:${SAVETO}"
+												else
+													let CHANGES++
+											fi
 										}
 		else
 			# ensure this does not remain in effect
 			unset SNAPMODIFIER R_SNAPMODIFIER
 	fi
 	
+	if [ $MODE == "backup" ]
+		then
 			# send backup
 			zfs send -Rcv${RAW_MOD}${SNAPMODIFIER} ${NEWSNAP} | ${RMOD:-$R_RMOD} zfs recv -Feu${RESUME_MOD}v ${SAVETO} 2>&1 >> ${LOGFILE}
 
 			# if replication is unsuccessful, omit the aging check so as to prevent data loss
-	if [ $? -eq 0 ]
+			if [[ ! ${PIPESTATUS[*]} =~ [1-9]+ ]]
 				then
+					let CHANGES++
 					THRESHOLD=$(( $KEEP * 24 * 3600 ))
 					for SNAPSHOT in ${SNAPSHOTS[*]}
 						do
@@ -135,8 +148,8 @@ function backup() {
 							fi
 						done
 				else
-			MY_EXIT_CODE=$?
-			logger -t $(basename ${0%.sh}) -p user.notice "failed to replicate ${NEWSNAP} (rc: $MY_EXIT_CODE) to ${TARGET:-local}:${SAVETO}, no aging"
+					logger -t $(basename ${0%.sh}) -p user.notice "failed to replicate ${NEWSNAP} to ${TARGET:-local}:${SAVETO}, no aging"
+			fi
 	fi
 
 	# re-evaluate snapshot data usage
@@ -148,6 +161,9 @@ function backup() {
 			R_RMOD="ssh ${USER}@${TARGET}"
 	fi
 			
+	if [ ${CHANGES:-0} -gt 0 ]
+		then
+			# calculate data volume change
 			R_USED_AFTER=$(snapuse ${SAVETO}/$( basename ${DATASET}))
 			L_DELTA=$(( $L_USED_AFTER - $L_USED_BEFORE ))
 			R_DELTA=$(( $R_USED_AFTER - ${R_USED_BEFORE:-0} ))
@@ -176,6 +192,7 @@ function backup() {
 							logger -t $(basename ${0%.sh}) -p user.notice "$_DELTA ${WHAT:-allocated} in \"${WHERE}\" by backing up \"${DATASET}\""
 					fi
 				done
+	fi
 
 	# reset remote configuration
 	unset R_RMOD RMOD RAW_MOD
@@ -274,12 +291,13 @@ LOGDIR="/var/log"
 # determine session logfile
 LOGFILE="${LOGDIR:-/tmp}/${ME}_${RUNDATE}.txt"
 
-while read -u 4 DATASET SAVETO KEEP ENABLED
+while read -u 4 DATASET SAVETO KEEP MODE ENABLED
 	# alternate file descriptor in use because SSH might be involved and we can not pass '-n' to it because we need stdin for 'zfs recv'
 	do
 		let COUNTER++
 		if [ ${ENABLED} == "Y" ]
 			then
+				# split this function -> snapshot(), sync(), age() ? -> a new backup() would call all three
 				backup
 		fi
 	done 4<<< "$(egrep -v '^(#|$)' "${CFGFILE}")" # graciously overlook any comments or blank lines