This post applies to users of Microsoft FAST search for SharePoint 2010.
Here are a few commands you can run on the FAST server to see if it’s healthy and also to get a feel if the back end is working in co-operation with the front end crawlers.
nctrl status will show if all the fast services are started and running.
indexerinfo status dumps some xml -the key piece here is the partitions – if you run indexerinfo status a few times, you should see some movement on these (percents will change)