From d854bae8a9decd8851707ba8aba418eaebed6ef8 Mon Sep 17 00:00:00 2001 From: Alasdair Kergon Date: Fri, 19 Aug 2011 17:36:13 +0000 Subject: [PATCH] tweak split/track/merge How do you discover the value of N? --- man/lvconvert.8.in | 35 +++++++++++++++++------------------ 1 file changed, 17 insertions(+), 18 deletions(-) diff --git a/man/lvconvert.8.in b/man/lvconvert.8.in index bd594687a..c57f365f8 100644 --- a/man/lvconvert.8.in +++ b/man/lvconvert.8.in @@ -125,12 +125,12 @@ a mirror logical volume. .TP .I \-\-trackchanges -This argument is used along with \-\-splitmirrors when the intention -is to use the split-off image temporarily in a read-only fashion. Splitting -off an image in this way allows it to be merged back into the mirror later -- only resynchronizing those portions of the image that have changed since -the split occurred. This option is only available to the "raid1" segment -type. +Used with \-\-splitmirrors on a raid1 device, this tracks changes so that the +read-only detached image can be merged efficiently back into the mirror later. +Only the regions of the detatched device where the data changed get resynchronized. + +Please note that this feature is only supported with the new md-based mirror +implementation and not with the original device-mapper mirror implementation. .br .TP @@ -146,7 +146,7 @@ Controls zeroing of the first KB of data in the snapshot. If the volume is read-only the snapshot will not be zeroed. .TP .I \-\-merge -Merges a snapshot into its origin volume or merges a RAID1 image that has +Merges a snapshot into its origin volume or merges a raid1 image that has been split from its mirror with \-\-trackchanges back into its mirror. To check if your kernel supports the snapshot merge feature, look @@ -164,7 +164,6 @@ be specified on the commandline or a @tag may be used to specify multiple snapshots be merged to their respective origin. .br - .TP .I \-\-repair Repair a mirror after suffering a disk failure. The mirror will be brought back @@ -238,20 +237,20 @@ volume will be linear. .br "lvconvert --splitmirrors 1 --trackchanges vg00/lv_raid1" .br -A mirrored logical volume that uses the "raid1" segment type (i.e. created -with '--type raid1') can use the '\-\-trackchanges' argument when splitting -off an image. The split-off image cannot be given a new name, as it is still -part of the original RAID1 logical volume in the sense that changes between -the two are being tracked for future integration upon merging. The device that -results from the split will be read-only and will be named similarly to the -original - in this case "lv_raid1_rimage_N", where 'N' is the index of the -image that has been split. +A mirrored logical volume created with --type raid1 can use the '\-\-trackchanges' argument when splitting +off an image. + +Detach one image from the mirrored logical volume lv_raid1 as a separate +read-only device and track the changes made to the mirror while it is detached. +The split-off device has a name of the form lv_raid1_rimage_N, where N is +a number, and it cannot be renamed. .br "lvconvert --merge vg00/lv_raid1_rimage_1" .br -Merge an image back into the mirror it was split from when the '\-\-trackchanges' -argument was used. +Merge an image that was detached temporarily from its mirror with +the '\-\-trackchanges' argument back into its original mirror and +bring its contents back up-to-date. .SH SEE ALSO .BR lvm (8),