Adar Dembo has posted comments on this change. ( http://gerrit.cloudera.org:8080/12075 )
Change subject: KUDU-2636: LBM supports deleting dead and full containers ...................................................................... Patch Set 2: (1 comment) http://gerrit.cloudera.org:8080/#/c/12075/1/src/kudu/fs/log_block_manager.cc File src/kudu/fs/log_block_manager.cc: http://gerrit.cloudera.org:8080/#/c/12075/1/src/kudu/fs/log_block_manager.cc@1179 PS1, Line 1179: : /////////////////////////////////////////////////////////// : // LogBlockCreationTransaction : //////////////// > Agree with point 1 and 3. Point 2 is spelled out in more detail in Repair(). I'll copy the relevant comment: // Delete all dead containers. // // After the deletions, the data directory is sync'ed to reduce the chance // of a data file existing without its corresponding metadata file (or vice // versa) in the event of a crash. The block manager would treat such a case // as corruption and require manual intervention. // // TODO(adar) the above is not fool-proof; a crash could manifest in between // any pair of deletions. That said, the odds of it happening are incredibly // rare, and manual resolution isn't hard (just delete the existing file). To go into more detail, the concern here is that once we start deleting files, a machine crash could lead to any subset of the deleted files coming back to life, regardless of the order in which they were deleted. Without a SyncDir() call, this vulnerability window is as long as the filesystem's journal commit period. On ext4 that's given by the 'commit' mount option, which defaults to 5s. -- To view, visit http://gerrit.cloudera.org:8080/12075 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: kudu Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I7d3672ae3c3dd9acd489120d653c44a641537f10 Gerrit-Change-Number: 12075 Gerrit-PatchSet: 2 Gerrit-Owner: helifu <[email protected]> Gerrit-Reviewer: Adar Dembo <[email protected]> Gerrit-Reviewer: Kudu Jenkins (120) Gerrit-Reviewer: helifu <[email protected]> Gerrit-Comment-Date: Thu, 13 Dec 2018 05:24:21 +0000 Gerrit-HasComments: Yes
