Secondary went into rollback mode, then generates a massive amount of logs (~18GB in less than 16 hours).

Sun Apr 28 14:06:41 [conn219706] command: unlock requested
Sun Apr 28 14:06:41 [rsSync] repl: old cursor isDead, will initiate a new one
Sun Apr 28 14:06:42 [rsSync] replSet syncing to: [primary address]:27017
Sun Apr 28 14:06:42 [rsSync] replSet our last op time written: Apr 28 12:01:41:1f
Sun Apr 28 14:06:42 [rsSync] replset source's GTE: Apr 28 13:01:00:20
Sun Apr 28 14:06:42 [rsSync] replSet rollback 0
Sun Apr 28 14:06:42 [rsSync] replSet ROLLBACK
Sun Apr 28 14:06:42 [rsSync] replSet rollback 1
Sun Apr 28 14:06:42 [rsSync] replSet rollback 2 FindCommonPoint
Sun Apr 28 14:06:42 [rsSync] replSet info rollback our last optime: Apr 28 12:01:41:1f
Sun Apr 28 14:06:42 [rsSync] replSet info rollback their last optime: Apr 28 14:06:42:22
Sun Apr 28 14:06:42 [rsSync] replSet info rollback diff in end of log times: -7501 seconds

FOLLOWED BY COUNTLESS SIMILAR TO:
Sun Apr 28 16:50:07 [rsSync] replSet WARNING ignoring op on rollback no _id TODO : inv.system.indexes
{ ts: Timestamp 1367150501000|31, h: -3893062772133308244, op: "i", ns: "inv.system.indexes", o: { u
nique: true, ns: "inv.fs.configs.chunks", name: "files_id_1_n_1", key:

} }

THEN THIS:
Sun Apr 28 16:49:08 [rsSync] replSet rollback error RS101 reached beginning of local oplog
Sun Apr 28 16:49:08 [rsSync] replSet them: [primary address]:27017 scanned: 40993835
Sun Apr 28 16:49:08 [rsSync] replSet theirTime: Jul 16 09:03:02 5003d8c6:13
Sun Apr 28 16:49:08 [rsSync] replSet ourTime: Apr 19 00:01:27 51708957:17
Sun Apr 28 16:49:08 [rsSync] replSet rollback 2 error RS101 reached beginning of local oplog [2]
Sun Apr 28 16:50:04 [rsSync] replSet syncing to: [primary address]:27017
Sun Apr 28 16:50:05 [rsSync] replSet our last op time written: Apr 28 12:01:41:1f
Sun Apr 28 16:50:05 [rsSync] replset source's GTE: Apr 28 13:01:00:20
Sun Apr 28 16:50:05 [rsSync] replSet rollback 0
Sun Apr 28 16:50:05 [rsSync] replSet rollback 1
Sun Apr 28 16:50:05 [rsSync] replSet rollback 2 FindCommonPoint
Sun Apr 28 16:50:05 [rsSync] replSet info rollback our last optime: Apr 28 12:01:41:1f
Sun Apr 28 16:50:05 [rsSync] replSet info rollback their last optime: Apr 28 16:50:05:6
Sun Apr 28 16:50:05 [rsSync] replSet info rollback diff in end of log times: -17304 seconds

It seems to simply repeat these patterns.