add note about TTL

tsa/howto/ganeti.mdwn

@@ -290,10 +290,16 @@ Import procedure:
  
         gnt-instance remove $INSTANCE
  
- 7. shutdown original instance:
+ 7. shutdown original instance in an hour:
  
-        ssh $INSTANCE shutdown -h +1 'migrating to new server'
+        ssh $INSTANCE shutdown -h +60 'migrating to new server'
  
+ 8. lower TTLs in the meantime
+ 
+    TODO: it is unclear how to do this. there is a `dnsTTL` record on
+    some hosts in DNS, but it's unclear when that takes effect, see
+    [ticket 33766](https://trac.torproject.org/projects/tor/ticket/33766) for details.
+
  8. redo migration as in step 3 and 4:
  
         ./ganeti -v -H $INSTANCE libvirt-import  --ganeti-node $SPARE_NODE --libvirt-host $KVM_HOST --adopt