According to DRBD documentation of replication mode.
Protocol C. Synchronous replication protocol. Local write operations on the primary node are considered completed only after both the local and the remote disk write have been confirmed. Refer http://www.drbd.org/users-guide/s-replication-protocols.html
So is there any chances that split brain occurs ? If I am using protocol C there is no chances that data will be partially written on one of the disk.
Is there any chances of data corruption/lost/mismatch of data b/w two nodes ?
This is a potentially harmful state, as it implies that modifications to the data might have been made on either node, without having been replicated to the peer. Thus, it is likely in this situation that two diverging sets of data have been created, which cannot be trivially merged. http://www.drbd.org/users-guide/s-split-brain-notification-and-recovery.html