Gitweb: http://git.fedorahosted.org/git/?p=lvm2.git;a=commitdiff;h=42d7409da27611987... Commit: 42d7409da2761198781e067b81a4dca86ba27ee9 Parent: 044b7968005a23e52a78c26eb56a7f74a973312f Author: David Teigland teigland@redhat.com AuthorDate: Wed May 14 14:05:21 2014 -0500 Committer: David Teigland teigland@redhat.com CommitterDate: Wed May 14 15:15:35 2014 -0500

man: lvmthin cover snapshot merge and xfs

also fix a couple inconsistent example values. --- man/lvmthin.7.in | 115 ++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 files changed, 112 insertions(+), 3 deletions(-)

diff --git a/man/lvmthin.7.in b/man/lvmthin.7.in index 5a4ee87..030745b 100644 --- a/man/lvmthin.7.in +++ b/man/lvmthin.7.in @@ -104,7 +104,7 @@ The primary method for using lvm thin provisioning: lvcreate -n ThinDataLV -L LargeSize VG

Example - # lvcreate -n pool0 -L 100G vg + # lvcreate -n pool0 -L 10G vg

2. create ThinMetaLV

@@ -251,6 +251,10 @@ Single step thin pool LV creation .br Single step thin pool LV and thin LV creation .br +Merge thin snapshots +.br +XFS on snapshots +.br

&

@@ -269,7 +273,7 @@ lvcreate -n ThinMetaLV -L SmallSize VG SmallPV lvconvert --thinpool VG/ThinDataLV --poolmetadata VG/ThinMetaLV

Example -# lvcreate -n pool0 -L 100G vg /dev/sdA +# lvcreate -n pool0 -L 10G vg /dev/sdA # lvcreate -n pool0meta -L 1G vg /dev/sdB # lvconvert --thinpool vg/pool0 --poolmetadata vg/pool0meta .fi @@ -293,7 +297,7 @@ lvcreate --type raid1 -m 1 -n ThinDataLV -L LargeSize VG PVC PVD lvconvert --thinpool VG/ThinDataLV --poolmetadata VG/ThinMetaLV

Example -# lvcreate --type raid1 -m 1 -n pool0 -L 100G vg /dev/sdA /dev/sdB +# lvcreate --type raid1 -m 1 -n pool0 -L 10G vg /dev/sdA /dev/sdB # lvcreate --type raid1 -m 1 -n pool0meta -L 1G vg /dev/sdC /dev/sdD # lvconvert --thinpool vg/pool0 --poolmetadata vg/pool0meta .fi @@ -981,6 +985,111 @@ pool0 vg twi-a-tz-- 8.00m thin1 vg Vwi-a-tz-- 2.00g pool0 .fi

+ +.SS Merge thin snapshots + +& + +A thin snapshot can be merged into its origin thin LV using the lvconvert +--merge command. The result of a snapshot merge is that the origin thin +LV takes the content of the snapshot LV, and the snapshot LV is removed. +Any content that was unique to the origin thin LV is lost after the merge. + +Because a merge changes the content of an LV, it cannot be done while the +LVs are open, e.g. mounted. If a merge is initiated while the LVs are open, +the effect of the merge is delayed until the origin thin LV is next +activated. + +.nf +lvconvert --merge VG/SnapLV + +Example +# lvs vg +LV VG Attr LSize Pool Origin +pool0 vg twi-a-tz-- 10.00g +thin1 vg Vwi-a-tz-- 100.00g pool0 +thin1s1 vg Vwi-a-tz-k 100.00g pool0 thin1 + +# lvconvert --merge vg/thin1s1 + +# lvs vg +LV VG Attr LSize Pool Origin +pool0 vg twi-a-tz-- 10.00g +thin1 vg Vwi-a-tz-- 100.00g pool0 +.fi + +.nf +Example + +Delayed merging of open LVs. + +# lvs vg +LV VG Attr LSize Pool Origin +pool0 vg twi-a-tz-- 10.00g +thin1 vg Vwi-aotz-- 100.00g pool0 +thin1s1 vg Vwi-aotz-k 100.00g pool0 thin1 + +# df +/dev/mapper/vg-thin1 100G 33M 100G 1% /mnt/X +/dev/mapper/vg-thin1s1 100G 33M 100G 1% /mnt/Xs + +# ls /mnt/X +file1 file2 file3 +# ls /mnt/Xs +file3 file4 file5 + +# lvconvert --merge vg/thin1s1 +Logical volume vg/thin1s1 contains a filesystem in use. +Delaying merge since snapshot is open. +Merging of thin snapshot thin1s1 will occur on next activation. + +# umount /mnt/X +# umount /mnt/Xs + +# lvs -a vg +LV VG Attr LSize Pool Origin +pool0 vg twi-a-tz-- 10.00g +[pool0_tdata] vg Twi-ao---- 10.00g +[pool0_tmeta] vg ewi-ao---- 1.00g +thin1 vg Owi-a-tz-- 100.00g pool0 +[thin1s1] vg Swi-a-tz-k 100.00g pool0 thin1 + +# lvchange -an vg/thin1 +# lvchange -ay vg/thin1 + +# mount /dev/vg/thin1 /mnt/X + +# ls /mnt/X +file3 file4 file5 +.fi + + +.SS XFS on snapshots + +& + +Mounting an XFS file system on a new snapshot LV requires attention to the +file system's log state and uuid. On the snapshot LV, the xfs log will +contain a dummy transaction, and the xfs uuid will match the uuid from the +file system on the origin LV. + +If the snapshot LV is writable, mounting will recover the log to clear the +dummy transaction, but will require skipping the uuid check: + +mount /dev/VG/SnapLV /mnt -o nouuid + +Or, the uuid can be changed on disk before mounting: + +xfs_admin -U generate /dev/VG/SnapLV +.br +mount /dev/VG/SnapLV /mnt + +If the snapshot LV is readonly, the log recovery and uuid check need to be +skipped while mounting readonly: + +mount /dev/VG/SnapLV /mnt -o ro,nouuid,norecovery + + .SH SEE ALSO .BR lvm (8), .BR lvm.conf (5),