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1

Let's assume we have lv path:

lvpath=/dev/mapper/vg2-Music

Than I split lvdisplay -c with cut:

vgname="$(lvdisplay -c "$lvpath" | cut -d ':' -f 2 )"
lvname="$(basename "$(lvdisplay -c "$lvpath" | cut -d ':' -f 1 )" )"

result:

$ echo VG: $vgname LV: $lvname
VG: vg2 LV: Music

question:

Is there more convenient way of doing this ?

Can I rely on lvdisplay -c that will always provide path in form /dev/VGname/LVname ? (In case of /dev/mapper/VGname-LVname basename sould be exchanged with sed)

Is there tool from LVM2 package to obtain LVname from path?

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There are many tools and switches for obtaining LVM info. Could you give an example of a use case for your need? Just from the path itself, you can't be certain that a lv doesn't have an embedded hyphen in it's name. – bdowning Mar 24 '12 at 16:06

2 Answers

up vote 2 down vote accepted

Use lvs with the -o option to customize the displayed fields.

set $(lvs --noheadings -o lv_name,vg_name)
lv_name=$1 vg_name=$2

Note that you can't just write lv_name=$(lvs --noheadings -o lv_name) because lvs puts extra whitespace around the value. The snippet is safe because volume names aren't allowed to contain shell special characters.

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Is lvname="$(echo `lvs --noheadings -o lv_name "$lvpath"`)" safe in your opinion ? – Grzegorz Wierzowiecki Mar 26 '12 at 14:38
@GrzegorzWierzowiecki It's safe but looks awfully complicated. – Gilles Mar 26 '12 at 16:49
I know, I just don't want to overwrite parameters $1 , $2 . On the other hand I can encapsulate your solution into function to prevent set of changing global parameters. Thanks :) – Grzegorz Wierzowiecki Mar 26 '12 at 19:46
up vote -2 down vote

Have you tried lvs (logical volume scan)? I added how the ouput looks after running lvs and some of the man page on lvs.

LV VG Attr LSize Origin Snap% Move Log Copy% Convert

lv_home vg_testing -wi-ao 113.75g

MAN info:

LVS(8) LVS(8)

NAME lvs - report information about logical volumes

SYNOPSIS lvs [-a|--all] [--aligned] [-d|--debug] [-h|-?|--help] [--ignorelock- ingfailure] [--nameprefixes] [--noheadings] [--nosuffix] [-o|--options [+]Field[,Field]] [-O|--sort [+|-]Key1[,[+|-]Key2[,...]]] [-P|--par- tial] [--rows] [--segments] [--separator Separator] [--unbuffered] [--units hHbBsSkKmMgGtTpPeE] [--unquoted] [-v|--verbose] [--version] [VolumeGroupName [VolumeGroupName...]]

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I looked at your script are you really trying to get the path or just the name of the logical volume? – Iman Mar 24 '12 at 14:51
I have no idea what you're trying to say in your answer, beyond “use lvs”, which is true but incomplete, and not useful the way you show it. – Gilles Mar 26 '12 at 0:29
lvs is one of most basic LVM commands – Grzegorz Wierzowiecki Mar 26 '12 at 14:32

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