Thanks for the answers. I wil do a restore Setup en configuration and hope that i got the replication task back.
The backup units holds now the Volume and is the source one.
De failed DSS (primary) is now destination. De data on the primary (failed DSS status destination) is not good so i must do a complete sync.
Where must i clear the metadata. On the backup unit where the volume is source or must i clear it on the failed one (primary) where the volume is destination.
On the failed Primary DSS if you clear the metadata in the Volume Replication keep in mind that this will do a full sync, again this is in the volume replication part of the GUI.
I have done a restore of the setup and configuration. De replication tasks are back.
I also cleared the metadata on the primary (failed DSS) en select Volume destination.
The last steps (correct me if i'am wrong) is: starting replication services on the primary DSS and select the sync button in the backup unit (wich hold the souce volume)
When the sync is completed i can do a fallback so that de primary is the active node en de backup DSS is the passive node.
I have selected the sync button and that is working. The speed is about 16000 kb/s wich is not so high. It takes 50h to complete.
But when the sync is starting the performance is realy bad. We have several terminal servers and when you login it takes 10 minutes to get in. Also the linux servers get a kernel panic. After the kernel panic i reboot the linux server but then they will not boot or it takes to long. I have shutdown the primary host and everything is working normal. I dont know what i can do now. Also i dont know how i can stop the sync. I have now shutdown the primary host otherwise he is starting the sync.
You can stop the Sync from the Volume Replication task, the sync needs to complete, make sure that the volume replication tasks is consistent to consistent for both Source and Destination in Status > Tasks, this is most likely the issue of your performance.