[ceph-users] Question about MDS cluster's behavior when crash occurs

Hi all. I have some questions about how MDS cluster works when crash or operation failure occur. 1. I read ceph documentation and code that each MDS has its own journal and some directory operations like rename use distributed transaction mechanism with ceph-defined events (e.g. EPeerUpdate). What I wonder is when one of MDSs is crashed and then reboots, if some metadata in other MDS's journal is not flushed yet, is rebooted MDS read stale metadata? 2. While rename operation is performing on 2 MDSs and one of them is crashed, Does the other MDS rollback modified in-memory metadata ? Thanks, kyujin