Crawl Status stuck on computing ranking - Backups do not complete

Hi,

We have a newly built sharepoint 2010 farm, using a WFE and Application server with a backend SQL.

As part of a previous issue we have recreated the seach service application. Since that point we are unable to complete a backup using the backup-spfarm command. (Backup-SPFarm -Directory\\xxx\spbackup -BackupMethod Full -Verbose)

The backup never completes, it does not error or complete sucessfully, and has to be terminated manually. The backup is then not restorable via the central admin.

We have attempted a backup of the search application only using the switch -Item "Search Service Application" on backup-spfarm, and this does not complete, but we are able to back up other components ok.

We have also noticed that the crawl status background activity changes to "computing ranking" and will  not change unless a full index reset is done. The crawl and searching is working as expected regardless of if its computing ranking or not.

We have already recreated the search application.

Here is a similar situation I found for 2007

http://social.technet.microsoft.com/Forums/en-US/sharepointsearch/thread/40270ed3-73b2-4133-925f-1daa71ea4ac0/

However this does not apply to us on 2010.