mongos> sh.moveChunk("offerStore.offer", { _id: 540867465 }, "offerStoreIT2");
{
        "cause" : {
                "cause" : {
                        "ok" : 0,
                        "errmsg" : "can't accept new chunks because  there are still 81 deletes from previous migration"
                },
                "ok" : 0,
                "errmsg" : "moveChunk failed to engage TO-shard in the data transfer: can't accept new chunks because  there are still 81 deletes from previous migration"
        },
        "ok" : 0,
        "errmsg" : "move failed"
}

mongos> db.changelog.find().sort({time:-1})
{ "_id" : "s163-2014-05-25T21:59:45-538267d121bb6c9634f5a4c0", "server" : "s163", "clientAddr" : "172.16.66.17:56136", "time" : ISODate("2014-05-25T21:59:45.234Z"), "what" : "moveChunk.from", "ns" : "offerStore.offer", "details" : { "min" : { "_id" : NumberLong(540867465) }, "max" : { "_id" : NumberLong(541166222) }, "step 1 of 6" : 0, "step 2 of 6" : 286, "note" : "aborted" } }
{ "_id" : "s163-2014-05-25T21:59:45-538267d121bb6c9634f5a4bf", "server" : "s163", "clientAddr" : "172.16.66.17:56136", "time" : ISODate("2014-05-25T21:59:45.061Z"), "what" : "moveChunk.start", "ns" : "offerStore.offer", "details" : { "min" : { "_id" : NumberLong(540867465) }, "max" : { "_id" : NumberLong(541166222) }, "from" : "offerStoreIT", "to" : "offerStoreIT2" } }