On 30/01/2017 21:15, Andriy Gapon wrote: > On 06/01/2017 12:12, Andriy Gapon wrote: >> To add more substance, here is what gets logged when the disk disappears: >> >> GEOM_MIRROR: Request failed (error=6). ada0p2[READ(offset=2517700608, >> length=4096)] >> GEOM_MIRROR: Device swap: provider ada0p2 disconnected. >> >> And here's what gets logged when the disk reappears: >> GEOM_MIRROR: Component ada0p2 (device swap) broken, skipping. >> GEOM_MIRROR: Cannot add disk ada0p2 to swap (error=22). > > I think I see a problem. > There are three places where G_MIRROR_DISK_STATE_DISCONNECTED event is posted: > 1. g_mirror_orphan() that is called when GEOM notifies us that a disk is gone > 2. g_mirror_regular_request(), when we get an error writing or reading data > 3. g_mirror_sync_request(), when e get an error writing data to a disk being > synchronized > 4. g_mirror_write_metadata() when we get an error while writing (updating) the > metadata to a member's label > > #1 is called when the disk disappears when there is no I/O. > If the disk disappears while there is some I/O, then we can get either #1 or > #2. > We can get #3 during disk re-synchronization. > We can get #4 in "rare" cases when we update the metadata (e.g. change the > mirror configuration). > > In case #1 the code sets G_MIRROR_BUMP_SYNCID flag before posting the event. > In cases #2, #3 and #4 the code sets G_MIRROR_BUMP_GENID flag. > > I believe that the code should set G_MIRROR_BUMP_GENID only in case #4. > In that case the metadata becomes different between the mirror members and, > thus, there is no way for the code to automatically rebuild the mirror. > > In cases #1, #2 and #3 only the data becomes stale on a member and, thus, > there > should be a chance to re-synchronize that member. In fact, in case #3 the > member is already being synchronized. > > I could be missing something, of course. > So, any comments and corrections are very welcome. > Thanks! >
At the very minimum I would like to change G_MIRROR_BUMP_GENID to G_MIRROR_BUMP_SYNCID in g_mirror_regular_request() for ENXIO. -- Andriy Gapon _______________________________________________ freebsd-geom@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-geom To unsubscribe, send any mail to "freebsd-geom-unsubscr...@freebsd.org"
