LPAR Migration Error Message- HSCLA24E

This week we where trying to migrate some VIO hosted LPARs using XIV disk from one POWER 7 system to another.  The disk is hosted on a VIO server via the fabric, then using vscsi devices to map up to the servers.  Unfortunately the migration failed and the message we got was -
 HSCLA24E The migrating partition's virtual SCSI adapter 2 cannot
 be hosted by the existing virtual I/O server (VIOS) partition on the
 destination managed system.  To migrate the partition, set up the
 necessary VIOS hosts on the destination managed system, then try
 the operation again.

So we did some searching and found the following -
HSCLA24E error:
1) On the source Virtual I/O Server partition, do not set the adapter as required and do not select Any client partition can connect when you create a virtual SCSI adapter. (can cause the error code).
2) max transfer size of the used hdisk may not be different on source and destination VIOS.
3) The VIO Servers may not have set the reserve_policy to single_path, no_reserve is required.
4) Destination VIO Servers are not able to see the disks the client needs.
5) the same VTD (Virtual target devices) names may not exist on the destination system.
 
But as we have XIV disk you also need to ensure that the following matches up on the source and destination system else it will fail as above:
 
Boot disks -
algorithm       fail_over
max_transfer    0x100000
queue_depth     256
Data disks -
algorithm       round_robin
max_transfer    0x100000
queue_depth     256
 
Setting the 'fail_over' on the boot disks is important as while you might be able to see the disk, 'round_robin' will cause the OS to fail to boot. If the information is different between the VIO Server you are migrating too and from then the migration will fail, so this means your need to perform some pre-activities to ensure it works.