+++ This bug was initially created as a clone of Bug #1393566 +++
The on-disk metadata used by dm-cache is being updated to allow for performance enhancements. LVM will need to pass down additional DM table arguments in order to activate these changes. We need to have a solution ready that is forward/backwards compatible.
--- Additional comment from Zdenek Kabelac on 2017-02-20 05:09:06 EST ---
So lets list the options:
lvm2 new parameter:
1.) --cacheversion 1|2|auto
2.) --cache-metadata-version 2 ?
3.) --metadata-version 2 ?
4.) --cacheformat 1|2|auto (or maybe this: v1|v2|auto ) ?
libdm API options:
1.) add new dm_tree_node_set_cache_version(....)
2.) add new dm_tree_node_set_cache_format(....)
3.) #define DM_CACHE_FEATURE_FORMAT_2
4.) #define DM_CACHE_FEATURE_FORMAT_V2
5.) #define DM_CACHE_FEATURE_VERSION_2
ATM I'd prefer the format to be automatically recognized by the 'cache_check' tool - as adding some 'magical' args by lvm2 to the existing configurable set can be problematic for a user - it could be done - but lvm2 will be changing passed option set.
i.e. it's then unclear if we should use:
cache_check --metadata-version 2
cache_check --metadata-version 1
or just use it with version 2 ?
Waiting for more judgment here.
Should we have a release note writeup fo this feature?
Marking this feature verified in the latest rpms.
All current cache scenarios passed with both --cachemetadataformat 2 and 1, as well as attempted activation on older (7.3,7.2) versions. See bug 1451459 for more information on up|downgrade testing.
lvm2-2.02.171-7.el7 BUILT: Thu Jun 22 08:35:15 CDT 2017
lvm2-libs-2.02.171-7.el7 BUILT: Thu Jun 22 08:35:15 CDT 2017
lvm2-cluster-2.02.171-7.el7 BUILT: Thu Jun 22 08:35:15 CDT 2017
device-mapper-1.02.140-7.el7 BUILT: Thu Jun 22 08:35:15 CDT 2017
device-mapper-libs-1.02.140-7.el7 BUILT: Thu Jun 22 08:35:15 CDT 2017
device-mapper-event-1.02.140-7.el7 BUILT: Thu Jun 22 08:35:15 CDT 2017
device-mapper-event-libs-1.02.140-7.el7 BUILT: Thu Jun 22 08:35:15 CDT 2017
device-mapper-persistent-data-0.7.0-0.1.rc6.el7 BUILT: Mon Mar 27 10:15:46 CDT 2017
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.