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lvm2/lib/mirror
Jonathan Brassow dd0ee35378 cmirror: Adjust region size to work around CPG msg limit to avoid hang.
cmirror uses the CPG library to pass messages around the cluster and maintain
its bitmaps.  When a cluster mirror starts-up, it must send the current state
to any joining members - a checkpoint.  When mirrors are large (or the region
size is small), the bitmap size can exceed the message limit of the CPG
library.  When this happens, the CPG library returns CPG_ERR_TRY_AGAIN.
(This is also a bug in CPG, since the message will never be successfully sent.)

There is an outstanding bug (bug 682771) that is meant to lift this message
length restriction in CPG, but for now we work around the issue by increasing
the mirror region size.  This limits the size of the bitmap and avoids any
issues we would otherwise have around checkpointing.

Since this issue only affects cluster mirrors, the region size adjustments
are only made on cluster mirrors.  This patch handles cluster mirror issues
involving pvmove, lvconvert (from linear to mirror), and lvcreate.  It also
ensures that when users convert a VG from single-machine to clustered, any
mirrors with too many regions (i.e. a bitmap that would be too large to
properly checkpoint) are trapped.
2015-02-25 14:42:15 -06:00
..
.exported_symbols Begin to separate out segment types. 2004-05-04 21:25:57 +00:00
Makefile.in Install plugins to subdirs 2010-05-06 10:07:46 +00:00
mirrored.c cmirror: Adjust region size to work around CPG msg limit to avoid hang. 2015-02-25 14:42:15 -06:00