Chunk size bigger than configured We have a sharded mongo cluster. We have configured the chunk size to be 256M but they are ~1.5G each. There are no jumbo chunks as our shard key is well balanced (we have also checked for them specifically). 
What can be the cause of having bigger than configured chunk sizes? And what can I do to auto split them?

EDIT

Shard Mongo at Mongo/
 data : 416.39GiB docs : 134529720 chunks : 368
 estimated data per chunk : 1.13GiB
 estimated docs per chunk : 365569

Shard db3repl at 
 data : 402.97GiB docs : 129491879 chunks : 372
 estimated data per chunk : 1.08GiB
 estimated docs per chunk : 348096

Shard db4repl at 
 data : 396.18GiB docs : 127334616 chunks : 368
 estimated data per chunk : 1.07GiB
 estimated docs per chunk : 346017

Shard db5repl at 
 data : 43.89GiB docs : 14141333 chunks : 368
 estimated data per chunk : 122.14MiB
 estimated docs per chunk : 38427
To split you can use something like this... 

sh.stopBalancer();
var c=0;
db.chunks.find({ns:"database.collection", "shard" : "S0RS0"}).sort({$natural:1}).limit(1400).forEach(function(d)
{
  printjson(d.min);printjson(d.max);
  var tulos=db.adminCommand( { split: d.ns, bounds: [ d.min, d.max ] } );
  if (tulos.ok &lt; 1) {
    print("Split ERROR");
    printjson(tulos);
  }
  print(c);
  c++;
})
sh.startBalancer();