On Tue, 1 Aug 2017 10:14:23 -0600 Liu Bo <bo.li....@oracle.com> wrote:
> This aims to fix write hole issue on btrfs raid5/6 setup by adding a > separate disk as a journal (aka raid5/6 log), so that after unclean > shutdown we can make sure data and parity are consistent on the raid > array by replaying the journal. Could it be possible to designate areas on the in-array devices to be used as journal? While md doesn't have much spare room in its metadata for extraneous things like this, Btrfs could use almost as much as it wants to, adding to size of the FS metadata areas. Reliability-wise, the log could be stored as RAID1 chunks. It doesn't seem convenient to need having an additional storage device around just for the log, and also needing to maintain its fault tolerance yourself (so the log device would better be on a mirror, such as mdadm RAID1? more expense and maintenance complexity). -- With respect, Roman -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
