Mongodump for oplog backup runs long

Hi,

For PITR we are taking oplog backup every one hour
The oplog is around 200GB and the backups run for almost 1.5hours
Is there a way we can speed the mongodump

{
        "ns" : "local.oplog.rs",
        "size" : 213203044962,
        "count" : 1265327007,
        "avgObjSize" : 168,
        "storageSize" : 37790625792,
        "capped" : true,

Thanks,
Tanveer