diff --git a/tests/cluster/tests/20-half-migrated-slot.tcl b/tests/cluster/tests/20-half-migrated-slot.tcl
new file mode 100644
index 000000000..6b5a8c516
--- /dev/null
+++ b/tests/cluster/tests/20-half-migrated-slot.tcl
@@ -0,0 +1,86 @@
+# Tests for fixing migrating slot at all stages:
+# 1. when migration is half inited on "migrating" node
+# 2. when migration is half inited on "importing" node
+# 3. migration inited, but not finished
+# 4. migration is half finished on "migrating" node
+# 5. migration is half finished on "importing" node
+source "../tests/includes/init-tests.tcl"
+source "../tests/includes/utils.tcl"
+
+test "Create a 2 nodes cluster" {
+    create_cluster 2 0
+}
+
+test "Cluster is up" {
+    assert_cluster_state ok
+}
+
+set cluster [redis_cluster 127.0.0.1:[get_instance_attrib redis 0 port]]
+catch {unset nodefrom}
+catch {unset nodeto}
+
+proc reset_cluster {} {
+    uplevel 1 {
+        $cluster refresh_nodes_map
+        array set nodefrom [$cluster masternode_for_slot 609]
+        array set nodeto [$cluster masternode_notfor_slot 609]
+    }
+}
+
+reset_cluster
+
+$cluster set aga xyz
+
+test "Half init migration in 'migrating' is fixable" {
+    $nodefrom(link) cluster setslot 609 migrating $nodeto(id)
+    fix_cluster $nodefrom(addr)
+    assert {[$cluster get aga] eq "xyz"}
+}
+
+test "Half init migration in 'importing' is fixable" {
+    $nodeto(link) cluster setslot 609 importing $nodefrom(id)
+    fix_cluster $nodefrom(addr)
+    assert {[$cluster get aga] eq "xyz"}
+}
+
+test "Init migration and move key" {
+    $nodefrom(link) cluster setslot 609 migrating $nodeto(id)
+    $nodeto(link) cluster setslot 609 importing $nodefrom(id)
+    $nodefrom(link) migrate $nodeto(host) $nodeto(port) aga 0 10000
+    assert {[$cluster get aga] eq "xyz"}
+    fix_cluster $nodefrom(addr)
+    assert {[$cluster get aga] eq "xyz"}
+}
+
+reset_cluster
+
+test "Move key again" {
+    $nodefrom(link) cluster setslot 609 migrating $nodeto(id)
+    $nodeto(link) cluster setslot 609 importing $nodefrom(id)
+    $nodefrom(link) migrate $nodeto(host) $nodeto(port) aga 0 10000
+    assert {[$cluster get aga] eq "xyz"}
+}
+
+test "Half-finish migration" {
+    # half finish migration on 'migrating' node
+    $nodefrom(link) cluster setslot 609 node $nodeto(id)
+    fix_cluster $nodefrom(addr)
+    assert {[$cluster get aga] eq "xyz"}
+}
+
+reset_cluster
+
+test "Move key back" {
+    # 'aga' key is in 609 slot
+    $nodefrom(link) cluster setslot 609 migrating $nodeto(id)
+    $nodeto(link) cluster setslot 609 importing $nodefrom(id)
+    $nodefrom(link) migrate $nodeto(host) $nodeto(port) aga 0 10000
+    assert {[$cluster get aga] eq "xyz"}
+}
+
+test "Half-finish importing" {
+    # Now we half finish 'importing' node
+    $nodeto(link) cluster setslot 609 node $nodeto(id)
+    fix_cluster $nodefrom(addr)
+    assert {[$cluster get aga] eq "xyz"}
+}
diff --git a/tests/cluster/tests/21-many-slot-migration.tcl b/tests/cluster/tests/21-many-slot-migration.tcl
new file mode 100644
index 000000000..62df0ce79
--- /dev/null
+++ b/tests/cluster/tests/21-many-slot-migration.tcl
@@ -0,0 +1,51 @@
+# Tests for many simlutaneous migrations.
+
+source "../tests/includes/init-tests.tcl"
+source "../tests/includes/utils.tcl"
+
+test "Create a 10 nodes cluster" {
+    create_cluster 10 10
+}
+
+test "Cluster is up" {
+    assert_cluster_state ok
+}
+
+set cluster [redis_cluster 127.0.0.1:[get_instance_attrib redis 0 port]]
+catch {unset nodefrom}
+catch {unset nodeto}
+
+$cluster refresh_nodes_map
+
+test "Set many keys" {
+    for {set i 0} {$i < 40000} {incr i} {
+        $cluster set key:$i val:$i
+    }
+}
+
+test "Keys are accessible" {
+    for {set i 0} {$i < 40000} {incr i} {
+        assert { [$cluster get key:$i] eq "val:$i" }
+    }
+}
+
+test "Init migration of many slots" {
+    for {set slot 0} {$slot < 1000} {incr slot} {
+        array set nodefrom [$cluster masternode_for_slot $slot]
+        array set nodeto [$cluster masternode_notfor_slot $slot]
+
+        $nodefrom(link) cluster setslot $slot migrating $nodeto(id)
+        $nodeto(link) cluster setslot $slot importing $nodefrom(id)
+    }
+}
+
+test "Fix cluster" {
+    fix_cluster $nodefrom(addr)
+}
+
+test "Keys are accessible" {
+    for {set i 0} {$i < 40000} {incr i} {
+        assert { [$cluster get key:$i] eq "val:$i" }
+    }
+}
+
diff --git a/tests/cluster/tests/includes/utils.tcl b/tests/cluster/tests/includes/utils.tcl
new file mode 100644
index 000000000..202db7350
--- /dev/null
+++ b/tests/cluster/tests/includes/utils.tcl
@@ -0,0 +1,17 @@
+source "../../../tests/support/cli.tcl"
+
+proc fix_cluster {addr} {
+    set code [catch {
+        exec ../../../src/redis-cli {*}[rediscli_tls_config "../../../tests"] --cluster fix $addr << yes
+    } result]
+    if {$code != 0 && $::verbose} {
+        puts $result
+    }
+    assert {$code == 0}
+    assert_cluster_state ok
+    wait_for_condition 1000 10 {
+        [catch {exec ../../../src/redis-cli {*}[rediscli_tls_config "../../../tests"] --cluster check $addr} _] == 0
+    } else {
+        fail "Cluster could not settle with configuration"
+    }
+}
diff --git a/tests/support/cluster.tcl b/tests/support/cluster.tcl
index fb8c46e75..97a659a1d 100644
--- a/tests/support/cluster.tcl
+++ b/tests/support/cluster.tcl
@@ -164,6 +164,28 @@ proc ::redis_cluster::__method__close {id} {
     catch {interp alias {} ::redis_cluster::instance$id {}}
 }
 
+proc ::redis_cluster::__method__masternode_for_slot {id slot} {
+    # Get the node mapped to this slot.
+    set node_addr [dict get $::redis_cluster::slots($id) $slot]
+    if {$node_addr eq {}} {
+        error "No mapped node for slot $slot."
+    }
+    return [dict get $::redis_cluster::nodes($id) $node_addr]
+}
+
+proc ::redis_cluster::__method__masternode_notfor_slot {id slot} {
+    # Get a node that is not mapped to this slot.
+    set node_addr [dict get $::redis_cluster::slots($id) $slot]
+    set addrs [dict keys $::redis_cluster::nodes($id)]
+    foreach addr [lshuffle $addrs] {
+        set node [dict get $::redis_cluster::nodes($id) $addr]
+        if {$node_addr ne $addr && [dict get $node slaveof] eq "-"} {
+            return $node
+        }
+    }
+    error "Slot $slot is everywhere"
+}
+
 proc ::redis_cluster::__dispatch__ {id method args} {
     if {[info command ::redis_cluster::__method__$method] eq {}} {
         # Get the keys from the command.
@@ -186,10 +208,15 @@ proc ::redis_cluster::__dispatch__ {id method args} {
 
         # Execute the command in the node we think is the slot owner.
         set retry 100
+        set asking 0
         while {[incr retry -1]} {
             if {$retry < 5} {after 100}
             set node [dict get $::redis_cluster::nodes($id) $node_addr]
             set link [dict get $node link]
+            if {$asking} {
+                $link ASKING
+                set asking 0
+            }
             if {[catch {$link $method {*}$args} e]} {
                 if {$link eq {} || \
                     [string range $e 0 4] eq {MOVED} || \
@@ -202,6 +229,7 @@ proc ::redis_cluster::__dispatch__ {id method args} {
                 } elseif {[string range $e 0 2] eq {ASK}} {
                     # ASK redirection.
                     set node_addr [lindex $e 2]
+                    set asking 1
                     continue
                 } else {
                     # Non redirecting error.
diff --git a/tests/support/util.tcl b/tests/support/util.tcl
index 886ef5020..c35441ab0 100644
--- a/tests/support/util.tcl
+++ b/tests/support/util.tcl
@@ -506,18 +506,18 @@ proc stop_write_load {handle} {
 
 proc K { x y } { set x } 
 
-# Shuffle a list. From Tcl wiki. Originally from Steve Cohen that improved
-# other versions. Code should be under public domain.
+# Shuffle a list with Fisher-Yates algorithm.
 proc lshuffle {list} {
     set n [llength $list]
-    while {$n>0} {
+    while {$n>1} {
         set j [expr {int(rand()*$n)}]
-        lappend slist [lindex $list $j]
         incr n -1
-        set temp [lindex $list $n]
-        set list [lreplace [K $list [set list {}]] $j $j $temp]
+        if {$n==$j} continue
+        set v [lindex $list $j]
+        lset list $j [lindex $list $n]
+        lset list $n $v
     }
-    return $slist
+    return $list
 }
 
 # Execute a background process writing complex data for the specified number