Error: Printing Stack Trace
    at printStackTrace (src/mongo/shell/utils.js:37:7)
    at doassert (src/mongo/shell/assert.js:6:1)
    at Function.assert.soon (src/mongo/shell/assert.js:110:48)
    at /data/buildslaves/Linux_RHEL_64bit_Nightly/mongo/jstests/slowNightly/sharding_migrateBigObject.js:43:8
Thu Feb 28 08:32:30.614 JavaScript execution failed: assert.soon failed: function (){ 
        res = mongos.getDB( "config" ).chunks.group( { cond : { ns : "test.stuff" } , 
                                                       key : { shard : 1 }  , 
                                                       reduce : function( doc , out ){ out.nChunks++; } , 
                                                       initial : { nChunks : 0 } } );
        
        printjson( res );
        return res.length > 1 && Math.abs( res[0].nChunks - res[1].nChunks ) <= 3;
    }, msg:never migrated at src/mongo/shell/assert.js:L7
failed to load: /data/buildslaves/Linux_RHEL_64bit_Nightly/mongo/jstests/slowNightly/sharding_migrateBigObject.js