diff --git a/hacking/aliZsync b/hacking/aliZsync
index 710482eac..9d33c286f 100755
--- a/hacking/aliZsync
+++ b/hacking/aliZsync
@@ -43,12 +43,13 @@ ProgName=$(basename $0)
 POOLNAME="${ALIZSYNC_POOL_NAME:-aliZsync}"
 POOLSIZE="${ALIZSYNC_POOL_SIZE:-100G}"
 IMG_FILE_PATH="${ALIZSYNC_IMG_FILE_PATH:-$HOME/$POOLNAME.img}"
+TRANSPORT="${ALIZSYNC_TRANSPORT:-mbuffer}"
 
 INVENTORY_FILE="${ALIZSYNC_INVENTORY:-/etc/o2.d/aliZsync_inventory}"
 TARGET_ROOT="${ALIZSYNC_TARGET_ROOT:-/opt/alizsw}"
 TIMESTAMP=$(date +"%Y-%m-%d_%H-%M-%S")
 TAG_NAME="${2:-$TIMESTAMP}"
-N_WORKERS="${ALIZSYNC_WORKERS:-8}"
+N_WORKERS="${ALIZSYNC_WORKERS:-10}"
 
 DATASET_SW="$POOLNAME/sw"
 DATASET_BINARIES="$DATASET_SW/slc7_x86-64"
@@ -72,9 +73,9 @@ sub_help(){
 
 sync_host(){
     HOST="$1"
-    $SYNC_CMD --sshIdentity "/root/.ssh/id_rsa_aliZsync" "$DATASET_BINARIES" "ssh://root@$HOST:alizsw/sw/slc7_x86-64"
+    $SYNC_CMD --transport "$TRANSPORT" --sshIdentity "/root/.ssh/id_rsa_aliZsync" "$DATASET_BINARIES" "ssh://root@$HOST:alizsw/sw/slc7_x86-64"
     echo -e "\t\t$HOST\tbinaries synchronized"
-    $SYNC_CMD --sshIdentity "/root/.ssh/id_rsa_aliZsync" "$DATASET_MODULES" "ssh://root@$HOST:alizsw/sw/MODULES"
+    $SYNC_CMD --transport "$TRANSPORT" --sshIdentity "/root/.ssh/id_rsa_aliZsync" "$DATASET_MODULES" "ssh://root@$HOST:alizsw/sw/MODULES"
     echo -e "\t\t$HOST\tmodules synchronized"
 }
 
@@ -128,6 +129,8 @@ sub_init(){
             HOST=$(echo "$LINE" | awk '{ print $1}')
             echo -e "\t$HOST"
             sshpass -p "$password" ssh-copy-id -i /root/.ssh/id_rsa_aliZsync "root@$HOST"
+            ssh -n -i /root/.ssh/id_rsa_aliZsync "root@$HOST" "firewall-cmd --zone=public --permanent --add-port=47099/tcp"
+            ssh -n -i /root/.ssh/id_rsa_aliZsync "root@$HOST" "firewall-cmd --reload"
         done < "$INVENTORY_FILE"
     fi
 
diff --git a/hacking/aliZsync-sync-zfs-snapshots.py b/hacking/aliZsync-sync-zfs-snapshots.py
index 95782ec33..a5395f00a 100755
--- a/hacking/aliZsync-sync-zfs-snapshots.py
+++ b/hacking/aliZsync-sync-zfs-snapshots.py
@@ -57,6 +57,7 @@ def main(argv):
     parser = argparse.ArgumentParser(description='Synchronise all snapshots in a ZFS filesystem to another zfs filesystem.  Useful for synchronising backups.')
 
     parser.add_argument ("--debug", dest='debug', nargs='?', const=1, type=int, help='Debug level of the application.  Uses debug 1 if flag is passed without a number.')
+    parser.add_argument ("--transport", dest='transport', nargs=1, help='transport to use for zfs send/receive, can be "mbuffer" (default) or "ssh"')
     parser.add_argument ("--sshIdentity", dest='sshIdentity', nargs=1, help='ssh identity key file to use when ssh-ing to destination servers')
     parser.add_argument ("source", help='Source ZFS filesystem.  Local filsystems are specified as zpool/filesystem.  Remote ones are specified as ssh://user@server[:port]:zpool/filesystem.')
     parser.add_argument ("destination", help='Destination ZFS filesystem.  Same format as source.')
@@ -90,22 +91,60 @@ def main(argv):
                 predecessorSubvolume = sourceSubvolumesByCreation[predecessorSubvolumeKey]
 
                 print ("# Missing subvolume:", sourceSubvolume, " predecessor:", predecessorSubvolume)
-                sendCmd = source.getZFSCmdLine (['/sbin/zfs', 'send', '-i', source.getZPoolFilesystem () + '@' + predecessorSubvolume, source.getZPoolFilesystem () + '@' + sourceSubvolume])
+                rawZfsSend = ['/sbin/zfs', 'send', '-i', source.getZPoolFilesystem () + '@' + predecessorSubvolume, source.getZPoolFilesystem () + '@' + sourceSubvolume]
+                sendCmd = source.getZFSCmdLine (rawZfsSend)
                 #print ("/sbin/zfs send -i "+ sourceZfsRoot + '@' + predecessorSubvolume + " " + sourceZfsRoot + '@' + sourceSubvolume + "| pv | ssh -p " + destinationPort + " " + " ".join(sshArgs) + " root@" + destinationServer + " /sbin/zfs receive -Fv " + destinationZfsRoot)
             else:
                 print ("# Missing initial subvolume:", sourceSubvolume)
-                sendCmd = source.getZFSCmdLine (['/sbin/zfs', 'send', source.getZPoolFilesystem () + '@' + sourceSubvolume])
-                #print ("/sbin/zfs send " + sourceZfsRoot + '@' + sourceSubvolume + "| pv | ssh -p " + destinationPort + " " + " ".join(sshArgs) + " root@" + destinationServer + " /sbin/zfs receive -Fv " + destinationZfsRoot)
+                rawZfsSend = ['/sbin/zfs', 'send', source.getZPoolFilesystem () + '@' + sourceSubvolume]
+                sendCmd = source.getZFSCmdLine (rawZfsSend)
+        #print ("/sbin/zfs send " + sourceZfsRoot + '@' + sourceSubvolume + "| pv | ssh -p " + destinationPort + " " + " ".join(sshArgs) + " root@" + destinationServer + " /sbin/zfs receive -Fv " + destinationZfsRoot)
 
+            rawZfsReceive = ['/sbin/zfs', 'receive', '-Fv', destination.getZPoolFilesystem ()]
             receiveCmd = destination.getZFSCmdLine (['/sbin/zfs', 'receive', '-Fv', destination.getZPoolFilesystem ()])
-            fullCmdLine = ' '.join (sendCmd) + ' | dd | ' + ' '.join (receiveCmd)
 
-            logLevel > 0 and print (fullCmdLine)
-            result = subprocess.call(fullCmdLine, shell = True)
+            if args.transport == ['ssh']:
+                fullCmdLine = ' '.join (sendCmd) + ' | dd | ' + ' '.join (receiveCmd)
 
-            if result:
-                print ("Error running:" + fullCmdLine)
-                sys.exit(1)
+                logLevel > 0 and print (fullCmdLine)
+                result = subprocess.call(fullCmdLine, shell = True)
+
+                if result:
+                    print ("Error running:" + fullCmdLine)
+                    sys.exit(1)
+            else:
+                fullReceiveLine = ' '.join (rawZfsReceive)
+                fullSendLine = ' '.join (rawZfsSend)
+                #first:
+                # mbuffer -4 -s 128k -m 1G -I 9090 | zfs receive data/filesystem
+                # then:
+                # zfs send -i data/filesystem@1 data/filesystem@2 | mbuffer -s 128k -m 1G -O 10.0.0.1:9090
+                remoteMvReceive = '"mbuffer -t -4 -s 512k -m 1G -I 47099 | ' + fullReceiveLine + '"'
+                mbReceive = ' '.join (destination.getZFSCmdLine([remoteMvReceive]))
+                print ("mbReceive:" + mbReceive)
+                mbSend = fullSendLine + ' | mbuffer -t -s 512k -m 1G -O ' + destination.server + ':47099'
+                print ("mbSend:" + mbSend)
+
+                spReceive = subprocess.Popen(mbReceive, shell=True)
+                print ("receive started")
+
+                time.sleep(1) # we wait for the receiver to be ready
+
+                spSend = subprocess.Popen(mbSend, shell=True)
+                print ("send started")
+
+                spSend.wait()
+                spReceive.wait()
+                # commands = [mbReceive, mbSend]
+                # procs = [ subprocess.Popen(i, shell = True) for i in commands ]
+                # for p in procs:
+                #     p.wait()
+
+                # to run on receiver:
+                # fuser -k -n tcp 47099
+                fuserKill = ' '.join (destination.getZFSCmdLine(['"fuser -k -n tcp 47099"']))
+                subprocess.call(fuserKill, shell=True)
+                print ("all done")
 
 
     #print ("########## Local volumes #######")