--- zfs-snapshot.orig	2016-01-05 01:44:44.000000000 +0100
+++ zfs-snapshot	2016-08-27 10:49:28.541901000 +0200
@@ -63,55 +63,65 @@
     type=$3
     skip=$4
 
-    # create the regex matching the type of snapshots we're currently working 
-    # on
-    case "$type" in
-        hourly)
-        # hourly-2009-01-01-00
-        regex="^$pool@$type-[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]-[0-9][0-9]$"
-        ;;
-        daily)
-        # daily-2009-01-01
-        regex="^$pool@$type-[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]$"
-        ;;
-        weekly)
-        # weekly-2009-01
-        regex="^$pool@$type-[0-9][0-9][0-9][0-9]-[0-9][0-9]"
-        ;;
-        monthly)
-        # monthly-2009-01
-        regex="^$pool@$type-[0-9][0-9][0-9][0-9]-[0-9][0-9]"
-        ;;
-        yearly)
-        # yearly-2009
-        regex="^$pool@$type-[0-9][0-9][0-9][0-9]"
-        ;;
-        *)
-        echo "unknown snapshot type: $type"
-        exit 1
-    esac
-
     create_snapshot $pool $type
+    clean_snapshots $pool $type
+}
+
+clean_snapshots()
+{
+    pool=$1
 
-    # get a list of all of the snapshots of this type sorted alpha, which
-    # effectively is increasing date/time
-    # (using sort as zfs's sort seems to have bugs)
-    snapshots=`zfs list -H -o name -t snapshot | sort | grep $regex`
-    # count them
-    count=`echo $snapshots | wc -w`
-    if [ $count -ge 0 ]; then
-        # how many items should we delete
-        delete=`expr $count - $keep`
-        count=0
-        # walk through the snapshots, deleting them until we've trimmed deleted
-        for snapshot in $snapshots; do
-            if [ $count -ge $delete ]; then
-                break
-            fi
-            delete_snapshot $snapshot
-            count=`expr $count + 1`
-        done
-    fi
+    # loop through datasets, do look for number of snapshots each
+    for dataset in $datasets; do
+
+        # create the regex matching the type of snapshots we're currently working 
+        # on
+        case "$type" in
+            hourly)
+            # hourly-2009-01-01-00
+            regex="^$dataset@$type-[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]-[0-9][0-9]$"
+            ;;
+            daily)
+            # daily-2009-01-01
+            regex="^$dataset@$type-[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]$"
+            ;;
+            weekly)
+            # weekly-2009-01
+            regex="^$dataset@$type-[0-9][0-9][0-9][0-9]-[0-9][0-9]"
+            ;;
+            monthly)
+            # monthly-2009-01
+            regex="^$dataset@$type-[0-9][0-9][0-9][0-9]-[0-9][0-9]"
+            ;;
+            yearly)
+            # yearly-2009
+            regex="^$dataset@$type-[0-9][0-9][0-9][0-9]"
+            ;;
+            *)
+            echo "unknown snapshot type: $type"
+            exit 1
+        esac
+
+        # get a list of all of the snapshots of this type sorted alpha, which
+        # effectively is increasing date/time
+        # (using sort as zfs's sort seems to have bugs)
+        snapshots=`zfs list -H -o name -t snapshot | sort | grep $regex`
+        # count them
+        count=`echo $snapshots | wc -w`
+        if [ $count -ge 0 ]; then
+            # how many items should we delete
+            delete=`expr $count - $keep`
+            count=0
+            # walk through the snapshots, deleting them until we've trimmed deleted
+            for snapshot in $snapshots; do
+                if [ $count -ge $delete ]; then
+                    break
+                fi
+                delete_snapshot $snapshot
+                count=`expr $count + 1`
+            done
+        fi
+    done
 }
 
 # take snapshots of type, for pools, keeping keep old ones,