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DescriptionJonathan Earl Brassow
2016-11-10 22:05:41 UTC
The RAID 4/5/6 kernel module/personality has support for journaling to solve the "write-hole" problem. This should be added to dm-raid.c/LVM.
Comment 2Heinz Mauelshagen
2016-11-16 16:19:15 UTC
*** Bug 1394052 has been marked as a duplicate of this bug. ***
Comment 3Heinz Mauelshagen
2016-11-16 16:50:26 UTC
raid5-cache.c provides 2 major features:
- journal stripes on a dedicated device to address the write hole caused
by non-atomic updates of N raid disks;
this obviously introduces latencies, thus slows down raid4/5/6 io
- allow for writeback caching of dirty journal entries in order to
compensate journalling penalties (upstream 11/10/2016);
this obviously introduces resilience issues WRT the journal device
thus requiring resilient types to be used
Comment 5Heinz Mauelshagen
2016-11-30 16:47:33 UTC
Comment 9Heinz Mauelshagen
2017-12-18 16:28:25 UTC
"[RHEL7.5 PATCH v2 00/17] dm raid: update to upstream fixing deadlocks/races"
to rhkernel-list on Dec 13
Comment 11Jonathan Earl Brassow
2018-01-09 15:56:15 UTC
This bug is for LVM integration, not kernel feature inclusion or updates. Moving back to ASSIGNED as there will be required LVM changes to make use of the kernel features.
Comment 13Heinz Mauelshagen
2019-12-05 17:26:00 UTC
Not planning to add to RHEL7.
Moving to RHEL8 which has support for journal device and modes (writeback and writethrough).
Comment 16RHEL Program Management
2020-12-01 07:27:37 UTC
After evaluating this issue, there are no plans to address it further or fix it in an upcoming release. Therefore, it is being closed. If plans change such that this issue will be fixed in an upcoming release, then the bug can be reopened.