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Commit Graph

22 Commits

Author SHA1 Message Date
Alasdair Kergon
d854bae8a9 tweak split/track/merge
How do you discover the value of N?
2011-08-19 17:36:13 +00:00
Jonathan Earl Brassow
a2facf4ad4 Add ability to merge back a RAID1 image that has been split w/ --trackchanges
Argument layout is very similar to the merge command for snapshots.
2011-08-18 19:43:08 +00:00
Jonathan Earl Brassow
6d04311efa Add the ability to split an image from the mirror and track changes.
~> lvconvert --splitmirrors 1 --trackchanges vg/lv
The '--trackchanges' option allows a user the ability to use an image of
a RAID1 array for the purposes of temporary read-only access.  The image
can be merged back into the array at a later time and only the blocks that
have changed in the array since the split will be resync'ed.  This
operation can be thought of as a partial split.  The image is never completely
extracted from the array, in that the array reserves the position the device
occupied and tracks the differences between the array and the split image via
a bitmap.  The image itself is rendered read-only and the name (<LV>_rimage_*)
cannot be changed.  The user can complete the split (permanently splitting the
image from the array) by re-issuing the 'lvconvert' command without the
'--trackchanges' argument and specifying the '--name' argument.
	~> lvconvert --splitmirrors 1 --name my_split vg/lv
Merging the tracked image back into the array is done with the '--merge'
option (included in a follow-on patch).
	~> lvconvert --merge vg/lv_rimage_<n>

The internal mechanics of this are relatively simple.  The 'raid' device-
mapper target allows for the specification of an empty slot in an array
via '- -'.  This is what will be used if a partial activation of an array
is ever required.  (It would also be possible to use 'error' targets in
place of the '- -'.)  If a RAID image is found to be both read-only and
visible, then it is considered separate from the array and '- -' is used
to hold it's position in the array.  So, all that needs to be done to
temporarily split an image from the array /and/ cause the kernel target's
bitmap to track (aka "mark") changes made is to make the specified image
visible and read-only.  To merge the device back into the array, the image
needs to be returned to the read/write state of the top-level LV and made
invisible.
2011-08-18 19:38:26 +00:00
Jonathan Earl Brassow
63bd9ec3ff Fix bug 635949: lvconvert man page clarification 2011-01-04 21:41:35 +00:00
Mike Snitzer
9443b5d4cd Convey need for snapshot-merge target in lvconvert error message and man
page.

Add ->target_name to segtype_handler to allow a more specific target
name to be returned based on the state of the segment.

Result of trying to merge a snapshot using a kernel that doesn't have
the snapshot-merge target:

Before:
# lvconvert --merge vg/snap
  Can't expand LV lv: snapshot target support missing from kernel?
  Failed to suspend origin lv

After:
# lvconvert --merge vg/snap
  Can't process LV lv: snapshot-merge target support missing from kernel?
  Failed to suspend origin lv
  Unable to merge LV "snap" into it's origin.
2010-10-13 21:26:37 +00:00
Jonathan Earl Brassow
94b713df08 Arguments to the --mirrorlog option are described in the synopsis as
{core|disk|mirrored}.  However, under the options section they are
described as {core|disk} - even though the 'mirrored' argument is
described.

s/'{core|disk}'/'{core|disk|mirrored}'/
2010-04-13 16:13:08 +00:00
Alasdair Kergon
68176be18e Add --stripes to lvconvert too. 2010-04-13 01:54:32 +00:00
Jonathan Earl Brassow
7a369d3704 Add ability to create mirrored logs for mirror LVs.
This check-in enables the 'mirrored' log type.  It can be specified
by using the '--mirrorlog' option as follows:
#> lvcreate -m1 --mirrorlog mirrored -L 5G -n lv vg

I've also included a couple updates to the testsuite.  These updates
include tests for the new log type, and some fixes to some of the
*lvconvert* tests.
2010-03-26 22:15:43 +00:00
Mike Snitzer
234b12480e lvconvert --merge @tag support
Switch lvconvert's --merge code over to using process_each_lv().  Doing
so adds support for a single 'lvconvert --merge' to start merging
multiple LVs (which includes @tag expansion).

Add 'lvconvert --merge @tag' testing to test/t-snapshot-merge.sh

Adjust man/lvconvert.8.in to reflect these expanded capabilities.

The lvconvert.c implementation requires rereading the VG each iteration
of process_each_lv().  Otherwise a stale VG instance associated with
the LV passed to lvconvert_single_merge() would result in stale VG
metadata being written back out to disk.  This overwrote new metadata
that was written when a previous snapshot LV finished merging (via
lvconvert_poll).  This is only an issue when merging multiple LVs that
share the same VG (a single VG is typical for most LVM configurations on
system disks).

In the end this new support is very useful for performing a "system
rollback" that requires multiple snapshot LVs be merged to their
respective origin LV.

The yum-utils 'fs-snapshot' plugin tags all snapshot LVs that it creates
with a common 'snapshot_tag' that is unique to the yum transaction.
Rolling back a yum transaction, that created LVM snapshots with the tag
'yum_20100129133223', is as simple as:
  lvconvert --merge @yum_20100129133223

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2010-02-05 22:44:37 +00:00
Mike Snitzer
a39ac3e11b Update lvconvert manpage for snapshot --merge 2010-01-13 01:55:05 +00:00
Alasdair Kergon
f3ac7d1b82 Revert so-called "redundant" log until after next release. 2010-01-12 14:00:51 +00:00
Jonathan Earl Brassow
77dd1c0e5f Add the new mirror log type "redundant". The options are now:
--mirrorlog core: in-memory log
--mirrorlog disk: persistent log
--mirrorlog redundant: redundant persistent log

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
2010-01-08 22:32:35 +00:00
Jonathan Earl Brassow
72e0743621 This patch adds the capability to split off a mirror legs.
It is pretty much the same as reducing the number of
mirror legs, but we just don't delete them afterwards.

The following command line interface is enforced:
  prompt> lvconvert --splitmirror <n> -n <name> <VG>/<LV>
where 'n' is the number of images to split off, and
where 'name' is the name of the newly split off logical volume.

If more than one leg is split off, a new mirror will be the
result.  The newly split off mirror will have a 'core' log.
Example:
[root@bp-01 LVM2]# !lvs
lvs -a -o name,copy_percent,devices
  LV            Copy%  Devices
  lv            100.00 lv_mimage_0(0),lv_mimage_1(0),lv_mimage_2(0),lv_mimage_3(0)
  [lv_mimage_0]        /dev/sdb1(0)
  [lv_mimage_1]        /dev/sdc1(0)
  [lv_mimage_2]        /dev/sdd1(0)
  [lv_mimage_3]        /dev/sde1(0)
  [lv_mlog]            /dev/sdi1(0)
[root@bp-01 LVM2]# lvconvert --splitmirrors 2 --name split vg/lv /dev/sd[ce]1
  Logical volume lv converted.
[root@bp-01 LVM2]# !lvs
lvs -a -o name,copy_percent,devices
  LV               Copy%  Devices
  lv               100.00 lv_mimage_0(0),lv_mimage_2(0)
  [lv_mimage_0]           /dev/sdb1(0)
  [lv_mimage_2]           /dev/sdd1(0)
  [lv_mlog]               /dev/sdi1(0)
  split            100.00 split_mimage_0(0),split_mimage_1(0)
  [split_mimage_0]        /dev/sde1(0)
  [split_mimage_1]        /dev/sdc1(0)

It can be seen that '--splitmirror <n>' is exactly the same
as '--mirrors -<n>' (note the minus sign), except there is the
additional notion to keep the image being detached from the
mirror instead of just throwing it away.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
2010-01-08 22:00:31 +00:00
Dave Wysochanski
23087fc917 Update lvcreate/lvconvert man pages to explain PhysicalVolume parameter.
Addresses rhbz 500177.
2009-10-26 13:41:13 +00:00
Dave Wysochanski
c808baef08 Update man pages to clarify usage of PE ranges.
Author: Dave Wysochanski <dwysocha@redhat.com>
2009-08-10 17:23:04 +00:00
Peter Rajnoha
c48b10050a '--noudevsync' -- update relevant man pages 2009-08-04 08:09:52 +00:00
Petr Rockai
e516e0708c Update synopsis in lvconvert manpage to mention --repair. 2009-08-02 21:01:51 +00:00
Alasdair Kergon
476d463348 pre-release tidy up 2009-06-30 18:39:31 +00:00
Milan Broz
c26488d348 Use lvconvert --repair instead of vgreduce in mirror dmeventd DSO (mornfall)
Introduce lvconvert --use_policies (mornfall)
2009-06-04 12:01:15 +00:00
Petr Rockai
eb23252b61 Implement, test and document (first iteration of) lvconvert --repair. 2009-04-23 16:56:21 +00:00
Dave Wysochanski
82dcb097c4 Make man pages consistent with either-or options (use "|" everywhere). 2008-11-12 15:01:35 +00:00
Alasdair Kergon
5951ef331a Generate man pages from templates and include version. (romster) 2008-10-08 12:50:13 +00:00