We have added a new shard to a 4 shard cluster making it 5 shards. The cluster is under a very light workload. Watching the load balancer it would appear that its going to take 2-3 days to complete rebalancing the shards.

> db.printShardingStatus();
— Sharding Status —
sharding version:

{ "_id" : 1, "version" : 3 }

shards:
{
"_id" : "repset_a",
"host" : "repset_a/lmdb-m03.mail.aol.com:7312,lmdb-d02.mail.aol.com:7312,lmdb-d01.mail.aol.com:7312"
}
{
"_id" : "repset_b",
"host" : "repset_b/lmdb-d05.mail.aol.com:7312,lmdb-m06.mail.aol.com:7312,lmdb-d04.mail.aol.com:7312"
}
{
"_id" : "repset_c",
"host" : "repset_c/lmdb-d03.mail.aol.com:7312,lmdb-m02.mail.aol.com:7312,lmdb-m01.mail.aol.com:7312"
}
{
"_id" : "repset_d",
"host" : "repset_d/lmdb-d06.mail.aol.com:7312,lmdb-m05.mail.aol.com:7312,lmdb-m04.mail.aol.com:7312"
}
{
"_id" : "repset_e",
"host" : "repset_e/lmdb-d08.mail.aol.com:7312,lmdb-m09.mail.aol.com:7312,lmdb-d07.mail.aol.com:7312"
}
databases:

{ "_id" : "admin", "partitioned" : false, "primary" : "config" } { "_id" : "MigOidDB", "partitioned" : true, "primary" : "repset_a" }

MigOidDB.MigOidCol chunks:
repset_e 205
repset_c 1283
repset_a 1283
repset_d 1283
repset_b 1283
too many chunksn to print, use verbose if you want to force print

{ "_id" : "test", "partitioned" : false, "primary" : "repset_a" } { "_id" : "local", "partitioned" : false, "primary" : "repset_a" } { "_id" : "MigOidCol", "partitioned" : false, "primary" : "repset_a" }

We have tried using moveChunk to speed the process up but the load balancer has a "Metadata Lock" on the collection and will not allow us to do a manual moveChunk.

> db.adminCommand({moveChunk : "MigOidDB.MigOidCol", find : {_id : "buggzeeann_30324171"}, to : "repset_e"});
{
"cause" : {
"who" : {
"_id" : "MigOidDB.MigOidCol",
"process" : "lmdb-d02.mail.aol.com:1303133674:1828878975",
"state" : 1,
"ts" : ObjectId("4db174cf7a18929e98aa4f5b"),
"when" : ISODate("2011-04-22T12:30:07.322Z"),
"who" : "lmdb-d02.mail.aol.com:1303133674:1828878975:conn34711:1543737603",
"why" : "migrate-

{ _id: \"ballc21_28406862\" }

"
},
"errmsg" : "the collection's metadata lock is taken",
"ok" : 0
},
"ok" : 0,
"errmsg" : "move failed"
}