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mirror of git://sourceware.org/git/lvm2.git synced 2024-12-21 13:34:40 +03:00
lvm2/lib/config
David Teigland 8b7a78c728 lvmcache: improve duplicate PV handling
Wait to compare and choose alternate duplicate devices until
after all devices are scanned.  During scanning, the first
duplicate dev is kept in lvmcache, and others are kept in a
new list (_found_duplicate_devs).

After all devices are scanned, compare all the duplicates
available for a given PVID and decide which is best.

If the dev used in lvmcache is changed, drop the old dev
from lvmcache entirely and rescan the replacement dev.
Previously the VG metadata from the old dev was kept in
lvmcache and only the dev was replaced.

A new config setting devices/allow_changes_with_duplicate_pvs
can be set to 0 which disallows modifying a VG or activating
LVs in it when the VG contains PVs with duplicate devices.
Set to 1 is the old behavior which allowed the VG to be
changed.

The logic for which of two devs is preferred has changed.
The primary goal is to choose a device that is currently
in use if the other isn't, e.g. by an active LV.

. prefer dev with fs mounted if the other doesn't, else
. prefer dev that is dm if the other isn't, else
. prefer dev in subsystem if the other isn't

If neither device is preferred by these rules, then don't
change devices in lvmcache, leaving the one that was found
first.

The previous logic for preferring a device was:

. prefer dev in subsystem if the other isn't, else
. prefer dev without holders if the other has holders, else
. prefer dev that is dm if the other isn't
2016-05-06 09:00:00 -05:00
..
config_settings.h lvmcache: improve duplicate PV handling 2016-05-06 09:00:00 -05:00
config.c doc: change fsf address 2016-01-21 12:11:37 +01:00
config.h doc: change fsf address 2016-01-21 12:11:37 +01:00
defaults.h lvmcache: improve duplicate PV handling 2016-05-06 09:00:00 -05:00