>No, the log end in the header is a hint. This is because we can't >atomically wrote to two objects (the header and the last log object) at the >same time, so we do atomic appends to the end of the log and flush out the >journal header lazily. Thanks; I get it now. >I believe zeroes at the end of the log are deliberate, as we "pre-zero" to >avoid some rare edge cases when MDSes restart and the log might have had >writes to later objects complete successfully while earlier ones were >blocked. If your MDS is not restarting it is probably because of the >non-zero data. I don't think my zeroes are pre-zeroing, as they actually occur in the middle of the final short object. As they start at what the log header says is the write point, my guess is that the MDS thought it flushed some stuff, so advanced the flush pointer, but in reality the write never happened. This failure to restart happened after the MDS crashed, and I lost any messages that would tell me why it crashed. I'll fix that and turn up verbosity and if it happens again, I'll have a better idea how the zeroes got there. -- Bryan Henderson San Jose, California _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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