Basic usage
We start our examples with default configuration - lvmconfig(8)
is helpful command to display configuration settings which are
currently used, including all configuration related to reporting.
We will use it throughout examples below to display current
configuration.
# lvmconfig --type full global/units global/suffix \
report/output_format report/compact_output \
report/compact_output_cols report/aligned \
report/headings report/separator \
report/list_item_separator report/prefixes \
report/quoted report/columns_as_rows \
report/binary_values_as_numeric report/time_format \
report/mark_hidden_devices report/two_word_unknown_device \
report/buffered
units="h"
suffix=1
output_format="basic"
compact_output=0
compact_output_cols=""
aligned=1
headings=1
separator=" "
list_item_separator=","
prefixes=0
quoted=1
columns_as_rows=0
binary_values_as_numeric=0
time_format="%Y-%m-%d %T %z"
mark_hidden_devices=1
two_word_unknown_device=0
buffered=1
Also, we start with simple LVM layout with two PVs (/dev/sda,
/dev/sdb), VG (vg) and two LVs (lvol0 and lvol1) in the VG. We
display all possible reports as single commands here, see also
pvs(8), vgs(8), lvs(8) man pages for more information. The field
set for each report type is configured with configuration
settings as we already mentioned in main report specifics section
in this man page.
# lvmconfig --type full report/pvs_cols report/pvs_sort \
report/pvsegs_cols report/pvsegs_sort report/vgs_cols \
report/vgs_sort report/lvs_cols report/lvs_sort \
report/segs_cols report/segs_sort
pvs_cols="pv_name,vg_name,pv_fmt,pv_attr,pv_size,pv_free"
pvs_sort="pv_name"
pvsegs_cols="pv_name,vg_name,pv_fmt,pv_attr,pv_size,pv_free,
pvseg_start,pvseg_size"
pvsegs_sort="pv_name,pvseg_start"
vgs_cols="vg_name,pv_count,lv_count,snap_count,vg_attr,vg_size,vg_free"
vgs_sort="vg_name"
lvs_cols="lv_name,vg_name,lv_attr,lv_size,pool_lv,origin,move_pv,
mirror_log,copy_percent,convert_lv"
lvs_sort="vg_name,lv_name"
segs_cols="lv_name,vg_name,lv_attr,stripes,segtype,seg_size"
segs_sort="vg_name,lv_name,seg_start"
# pvs
PV VG Fmt Attr PSize PFree
/dev/sda vg lvm2 a-- 100.00m 88.00m
/dev/sdb vg lvm2 a-- 100.00m 92.00m
# pvs --segments
PV VG Fmt Attr PSize PFree Start SSize
/dev/sda vg lvm2 a-- 100.00m 88.00m 0 1
/dev/sda vg lvm2 a-- 100.00m 88.00m 1 1
/dev/sda vg lvm2 a-- 100.00m 88.00m 2 1
/dev/sda vg lvm2 a-- 100.00m 88.00m 3 22
/dev/sdb vg lvm2 a-- 100.00m 92.00m 0 1
/dev/sdb vg lvm2 a-- 100.00m 92.00m 1 1
/dev/sdb vg lvm2 a-- 100.00m 92.00m 2 23
# vgs
VG #PV #LV #SN Attr VSize VFree
vg 2 2 0 wz--n- 200.00m 180.00m
# lvs
LV VG Attr LSize Pool Origin Move Log Cpy%Sync Convert
lvol0 vg -wi-a----- 4.00m
lvol1 vg rwi-a-r--- 4.00m 100.00
# lvs --segments
LV VG Attr #Str Type SSize
lvol0 vg -wi-a----- 1 linear 4.00m
lvol1 vg rwi-a-r--- 2 raid1 4.00m
We will use report/lvs_cols and report/lvs_sort configuration
settings to define our own list of fields to use and to sort by
that is different from defaults. You can do this for other
reports in same manner with
report/{pvs,pvseg,vgs,seg}_{cols,sort} configuration settings.
Also note that in the example below, we don't display the
"lv_time" field even though we're using it for sorting - this is
allowed.
# lvmconfig --type full report/lvs_cols report/lvs_sort
lvs_cols="lv_name,lv_size,origin,pool_lv,copy_percent"
lvs_sort="-lv_time"
# lvs
LV LSize Origin Pool Cpy%Sync
lvol1 4.00m 100.00
lvol0 4.00m
You can use -o|--options command line option to override current
configuration directly on command line.
# lvs -o lv_name,lv_size
LV LSize
lvol1 4.00m
lvol0 4.00m
# lvs -o+lv_layout
LV LSize Origin Pool Cpy%Sync Layout
lvol1 4.00m 100.00 raid,raid1
lvol0 4.00m linear
# lvs -o-origin
LV LSize Pool Cpy%Sync
lvol1 4.00m 100.00
lvol0 4.00m
# lvs -o lv_name,lv_size,origin -o+lv_layout -o-origin -O lv_name
LV LSize Layout
lvol0 4.00m linear
lvol1 4.00m raid,raid1
You can obtain the same information with single command where all
the information about PVs, PV segments, LVs and LV segments are
obtained per VG under a single VG lock for consistency, see also
lvm fullreport(8) man page for more information. The fullreport
has its own configuration settings to define field sets to use,
similar to individual reports as displayed above, but
configuration settings have "_full" suffix now. This way, it's
possible to configure different sets of fields to display and to
sort by for individual reports as well as the full report.
# lvmconfig --type full report/pvs_cols_full \
report/pvs_sort_full report/pvsegs_cols_full \
report/pvsegs_sort_full report/vgs_cols_full \
report/vgs_sort_full report/lvs_cols_full \
report/lvs_sort_full report/segs_cols_full \
report/segs_sort_full
pvs_cols_full="pv_name,vg_name"
pvs_sort_full="pv_name"
pvsegs_cols_full="pv_name,pvseg_start,pvseg_size"
pvsegs_sort_full="pv_uuid,pvseg_start"
vgs_cols_full="vg_name"
vgs_sort_full="vg_name"
lvs_cols_full="lv_name,vg_name"
lvs_sort_full="vg_name,lv_name"
segs_cols_full="lv_name,seg_start,seg_size"
segs_sort_full="lv_uuid,seg_start"
# lvm fullreport
VG
vg
PV VG
/dev/sda vg
/dev/sdb vg
LV VG
lvol0 vg
lvol1 vg
PV Start SSize
/dev/sda 0 1
/dev/sda 1 1
/dev/sda 2 1
/dev/sda 3 22
/dev/sdb 0 1
/dev/sdb 1 1
/dev/sdb 2 23
LV Start SSize
lvol0 0 4.00m
lvol1 0 4.00m
Automatic output compaction
If you look at the lvs output above, you can see that the report
also contains fields for which there is no information to display
(e.g. the columns under "Origin" and "Pool" heading - the
"origin" and "pool_lv" fields). LVM can automatically compact
report output so such fields are not included in final output. To
enable this feature and to compact all fields, use
report/compact_output=1 in your configuration.
# lvmconfig --type full report/compact_output
compact_output=1
# lvs
LV LSize Cpy%Sync
lvol1 4.00m 100.00
lvol0 4.00m
# lvs vg/lvol0
LV LSize
lvol0 4.00m
Alternatively, you can define which fields should be compacted by
configuring report/compact_output_cols configuration setting (or
-o|--options # command line option).
# lvmconfig --type full report/compact_output report/compact_output_cols
compact_output=0
compact_output_cols="origin"
# lvs
LV LSize Pool Cpy%Sync
lvol1 4.00m 100.00
lvol0 4.00m
# lvs vg/lvol0
LV LSize Pool
lvol0 4.00m
# lvs -o#pool_lv
LV LSize Origin Cpy%Sync
lvol1 4.00m 100.00
lvol0 4.00m
We will use report/compact_output=1 for subsequent examples.
Further formatting options
By default, LVM displays sizes in reports in human-readable form
which means that the most suitable unit is used so it's easy to
read. You can use report/units configuration setting (or --units
option directly on command line) and report/suffix configuration
setting (or --nosuffix command line option) to change this.
# lvs --units b --nosuffix
LV LSize Cpy%Sync
lvol1 4194304 100.00
lvol0 4194304
If you want to configure whether report headings are displayed or
not, use report/headings configuration settings (or --noheadings
command line option).
# lvs --noheadings
lvol1 4.00m 100.00
lvol0 4.00m
In some cases, it may be useful to display report content as
key=value pairs where key here is actually the field name. Use
report/prefixes configuration setting (or --nameprefixes command
line option) to switch between standard output and the key=value
output. The key=value pair is the output that is suitable for use
in scripts and for other tools to parse easily. Usually, you
also don't want to display headings with the output that has
these key=value pairs.
# lvs --noheadings --nameprefixes
LVM2_LV_NAME='lvol1' LVM2_LV_SIZE='4.00m' LVM2_COPY_PERCENT='100.00'
LVM2_LV_NAME='lvol0' LVM2_LV_SIZE='4.00m' LVM2_COPY_PERCENT=''
To define whether quotation marks in key=value pairs should be
used or not, use report/quoted configuration setting (or
--unquoted command line option).
# lvs --noheadings --nameprefixes --unquoted
LVM2_LV_NAME=lvol1 LVM2_LV_SIZE=4.00m LVM2_COPY_PERCENT=100.00
LVM2_LV_NAME=lvol0 LVM2_LV_SIZE=4.00m LVM2_COPY_PERCENT=
For easier parsing, you can even transpose the report so each
column now becomes a row in the output. This is done with
report/output_as_rows configuration setting (or --rows command
line option).
# lvs --noheadings --nameprefixes --unquoted --rows
LVM2_LV_NAME=lvol1 LVM2_LV_NAME=lvol0
LVM2_LV_SIZE=4.00m LVM2_LV_SIZE=4.00m
LVM2_COPY_PERCENT=100.00 LVM2_COPY_PERCENT=
Use report/separator configuration setting (or --separator
command line option) to define your own field separator to use.
# lvs --noheadings --nameprefixes --unquoted --separator " | "
LVM2_LV_NAME=lvol1 | LVM2_LV_SIZE=4.00m | LVM2_COPY_PERCENT=100.00
LVM2_LV_NAME=lvol0 | LVM2_LV_SIZE=4.00m | LVM2_COPY_PERCENT=
If you are using your own separator, the columns in the output
are not aligned by default. Use report/aligned configuration
setting (or --aligned command line option) for LVM to add extra
spaces in report to align the output properly.
# lvs --separator " | "
LV | LSize | Cpy%Sync
lvol1 | 4.00m | 100.00
lvol0 | 4.00m |
# lvs --separator " | " --aligned
LV | LSize | Cpy%Sync
lvol1 | 4.00m | 100.00
lvol0 | 4.00m |
Let's display one one more field in addition ("lv_tags" in this
example) for the lvs report output.
# lvs -o+lv_tags
LV LSize Cpy%Sync LV Tags
lvol1 4.00m 100.00
lvol0 4.00m tagA,tagB
The "LV Tags" column in the example above displays two list
values, separated by "," character for LV lvol0. If you need
different list item separator, use report/list_item_separator
configuration setting its definition.
# lvmconfig --type full report/list_item_separator
list_item_separator=";"
# lvs -o+tags
LV LSize Cpy%Sync LV Tags
lvol1 4.00m 100.00
lvol0 4.00m tagA;tagB
But let's still use the original "," character for
list_item_separator for subsequent examples.
Format for any of time values displayed in reports can be
configured with report/time_format configuretion setting. By
default complete date and time is displayed, including timezone.
# lvmconfig --type full report/time_format
time_format="%Y-%m-%d %T %z"
# lvs -o+time
LV LSize Cpy%Sync CTime
lvol1 4.00m 100.00 2016-08-29 12:53:36 +0200
lvol0 4.00m 2016-08-29 10:15:17 +0200
We can change time format in similar way as we do when using
date(1) command or strftime(3) function (lvmconfig --type default
--withcomments report/time_format will give you complete list of
available formatting options). In the example below, we decided
to use %s for number of seconds since Epoch (1970-01-01 UTC).
# lvmconfig --type full report/time_format
time_format="%s"
# lvs
LV Attr LSize Cpy%Sync LV Tags CTime
lvol1 rwi-a-r--- 4.00m 100.00 1472468016
lvol0 -wi-a----- 4.00m tagA,tagB 1472458517
The lvs does not display hidden LVs by default - to include these
LVs in the output, you need to use -a|--all command line option.
Names for these hidden LVs are displayed within square brackets.
# lvs -a
LV LSize Cpy%Sync
lvol1 4.00m 100.00
[lvol1_rimage_0] 4.00m
[lvol1_rmeta_0] 4.00m
[lvol1_rimage_1] 4.00m
[lvol1_rmeta_1] 4.00m
lvol0 4.00m
You can configure LVM to display the square brackets for hidden
LVs or not with report/mark_hidden_devices configuration setting.
# lvmconfig --type full report/mark_hidden_devices
mark_hidden_devices=0
# lvs -a
LV LSize Cpy%Sync
lvol1 4.00m 100.00
lvol1_rimage_0 4.00m
lvol1_rmeta_0 4.00m
lvol1_rimage_1 4.00m
lvol1_rmeta_1 4.00m
lvol0 4.00m
It's not recommended to use LV marks for hidden devices to decide
whether the LV is the one to use by end users or not. Please, use
"lv_role" field instead which can report whether the LV is
"public" or "private". The private LVs are used by LVM only and
they should not be accessed directly by end users.
# lvs -a -o+lv_role
LV LSize Cpy%Sync Role
lvol1 4.00m 100.00 public
lvol1_rimage_0 4.00m private,raid,image
lvol1_rmeta_0 4.00m private,raid,metadata
lvol1_rimage_1 4.00m private,raid,image
lvol1_rmeta_1 4.00m private,raid,metadata
lvol0 4.00m public
Some of the reporting fields that LVM reports are of binary
nature. For such fields, it's either possible to display word
representation of the value (this is used by default) or numeric
value (0/1 or -1 in case the value is undefined).
# lvs -o+lv_active_locally
LV LSize Cpy%Sync ActLocal
lvol1 4.00m 100.00 active locally
lvol0 4.00m active locally
We can change the way how these binary values are displayed with
report/binary_values_as_numeric configuration setting.
# lvmconfig --type full report/binary_values_as_numeric
binary_values_as_numeric=1
# lvs -o+lv_active_locally
LV LSize Cpy%Sync ActLocal
lvol1 4.00m 100.00 1
lvol0 4.00m 1
Changing output format
LVM can output reports in different formats - use
report/output_format configuration setting (or --reportformat
command line option) to swith the report output format.
Currently, LVM supports "basic" (all the examples we used above
used this format) and "JSON" output format.
# lvs -o lv_name,lv_size --reportformat json
{
"report": [
{
"lv": [
{"lv_name":"lvol1", "lv_size":"4.00m"},
{"lv_name":"lvol0", "lv_size":"4.00m"}
]
}
]
}
Note that some configuration settings and command line options
have no effect with certain report formats. For example, with
JSON output, it doesn't have any meaning to use report/aligned
(--aligned), report/noheadings (--noheadings),
report/columns_as_rows (--rows) or report/buffered
(--unbuffered). All these configuration settings and command line
options are ignored if using the JSON report output format.
Selection
If you need to select only specific rows from report, you can use
LVM's report selection feature. If you call lvm -S help, you'll
get quick help on selection. The help contains list of all fields
that LVM can use in reports together with its type enclosed in
square brackets. The example below contains a line from lvs -S
help.
# lvs -S help
...
lv_size - Size of LV in current units. [size]
...
This line tells you you that the "lv_size" field is of "size"
type. If you look at the bottom of the help output, you can see
section about "Selection operators" and its "Comparison
operators".
# lvs -S help
...
Selection operators
-------------------
Comparison operators:
=~ - Matching regular expression. [regex]
!~ - Not matching regular expression. [regex]
= - Equal to. [number, size, percent, string, string list, time]
!= - Not equal to. [number, size, percent, string, string_list, time]
>= - Greater than or equal to. [number, size, percent, time]
> - Greater than. [number, size, percent, time]
<= - Less than or equal to. [number, size, percent, time]
< - Less than. [number, size, percent, time]
since - Since specified time (same as '>='). [time]
after - After specified time (same as '>'). [time]
until - Until specified time (same as '<='). [time]
before - Before specified time (same as '<'). [time]
...
Here you can match comparison operators that you may use with the
"lv_size" field which is of type "size" - it's =, !=, >=, >, <=
and <. You can find applicable comparison operators for other
fields and other field types the same way.
To demonstrate selection functionality in LVM, we will create
more LVs in addition to lvol0 and lvol1 we used in our previous
examples.
# lvs -o name,size,origin,snap_percent,tags,time
LV LSize Origin Snap% LV Tags CTime
lvol4 4.00m lvol2 24.61 2016-09-09 16:57:44 +0200
lvol3 4.00m lvol2 5.08 2016-09-09 16:56:48 +0200
lvol2 8.00m tagA,tagC,tagD 2016-09-09 16:55:12 +0200
lvol1 4.00m 2016-08-29 12:53:36 +0200
lvol0 4.00m tagA,tagB 2016-08-29 10:15:17 +0200
When selecting size and percent fields, we don't need to use
units. For sizes, default "m" (for MiB) is used - this is the
same behaviour as already used for LVM commands when specifying
sizes (e.g. lvcreate -L). For percent fields, "%" is assumed
automatically if it's not specified. The example below also
demonstrates how several criteria can be combined together.
# lvs -o name,size,snap_percent -S 'size=8m'
LV LSize
lvol2 8.00m
# lvs -o name,size,snap_percent -S 'size=8'
LV LSize
lvol2 8.00m
# lvs -o name,size,snap_percent -S 'size < 5000k'
LV LSize Snap%
lvol4 4.00m 24.61
lvol3 4.00m 5.08
lvol1 4.00m
lvol0 4.00m
# lvs -o name,size,snap_percent -S 'size < 5000k && snap_percent > 20'
LV LSize Snap%
lvol4 4.00m 24.61
# lvs -o name,size,snap_percent \
-S '(size < 5000k && snap_percent > 20%) || name=lvol2'
LV LSize Snap%
lvol4 4.00m 24.61
lvol2 8.00m
You can also use selection together with processing-oriented
commands.
# lvchange --addtag test -S 'size < 5000k'
Logical volume vg/lvol1 changed.
Logical volume vg/lvol0 changed.
Logical volume vg/lvol3 changed.
Logical volume vg/lvol4 changed.
# lvchange --deltag test -S 'tags = test'
Logical volume vg/lvol1 changed.
Logical volume vg/lvol0 changed.
Logical volume vg/lvol3 changed.
Logical volume vg/lvol4 changed.
LVM can recognize more complex values used in selection criteria
for string list and time field types. For string lists, you can
match whole list strictly, its subset or intersection. Let's take
"lv_tags" field as an example - we select only rows which contain
"tagA" within tags field. We're using { } to denote that we're
interested in subset that matches. If the subset has only one
item, we can leave out { }.
# lvs -o name,tags -S 'tags={tagA}'
LV LV Tags
lvol2 tagA,tagC,tagD
lvol0 tagA,tagB
# lvs -o name,tags -S 'tags=tagA'
LV LV Tags
lvol2 tagA,tagC,tagD
lvol0 tagA,tagB
Depending on whether we use "&&" (or ",") or "||" ( or "#") as
delimiter for items in the set we define in selection criterion
for string list, we either match subset ("&&" or ",") or even
intersection ("||" or "#").
# lvs -o name,tags -S 'tags={tagA,tagC,tagD}'
LV LV Tags
lvol2 tagA,tagC,tagD
# lvs -o name,tags -S 'tags={tagA || tagC || tagD}'
LV LV Tags
lvol2 tagA,tagC,tagD
lvol0 tagA,tagB
To match the complete set, use [ ] with "&&" (or ",") as
delimiter for items. Also note that the order in which we define
items in the set is not relevant.
# lvs -o name,tags -S 'tags=[tagA]'
# lvs -o name,tags -S 'tags=[tagB,tagA]'
LV LV Tags
lvol0 tagA,tagB
If you use [ ] with "||" (or "#"), this is exactly the same as
using { }.
# lvs -o name,tags -S 'tags=[tagA || tagC || tagD]'
LV LV Tags
lvol2 tagA,tagC,tagD
lvol0 tagA,tagB
To match a set with no items, use "" to denote this (note that we
have output compaction enabled so the "LV Tags" column is not
displayed in the example below because it's blank and so it gets
compacted).
# lvs -o name,tags -S 'tags=""'
LV
lvol4
lvol3
lvol1
# lvs -o name,tags -S 'tags!=""'
LV LV Tags
lvol2 tagA,tagC,tagD
lvol0 tagA,tagB
When doing selection based on time fields, we can use either
standard, absolute or freeform time expressions in selection
criteria. Examples below are using standard forms.
# lvs -o name,time
LV CTime
lvol4 2016-09-09 16:57:44 +0200
lvol3 2016-09-09 16:56:48 +0200
lvol2 2016-09-09 16:55:12 +0200
lvol1 2016-08-29 12:53:36 +0200
lvol0 2016-08-29 10:15:17 +0200
# lvs -o name,time -S 'time since "2016-09-01"'
LV CTime
lvol4 2016-09-09 16:57:44 +0200
lvol3 2016-09-09 16:56:48 +0200
lvol2 2016-09-09 16:55:12 +0200
# lvs -o name,time -S 'time since "2016-09-09 16:56"'
LV CTime
lvol4 2016-09-09 16:57:44 +0200
lvol3 2016-09-09 16:56:48 +0200
# lvs -o name,time -S 'time since "2016-09-09 16:57:30"'
LV CTime
lvol4 2016-09-09 16:57:44 +0200
# lvs -o name,time \
-S 'time since "2016-08-29" && time until "2016-09-09 16:55:12"'
LV CTime
lvol2 2016-09-09 16:55:12 +0200
lvol1 2016-08-29 12:53:36 +0200
lvol0 2016-08-29 10:15:17 +0200
# lvs -o name,time \
-S 'time since "2016-08-29" && time before "2016-09-09 16:55:12"'
LV CTime
lvol1 2016-08-29 12:53:36 +0200
lvol0 2016-08-29 10:15:17 +0200
Time operators have synonyms: ">=" for since, "<=" for until, ">"
for "after" and "<" for "before".
# lvs -o name,time \
-S 'time >= "2016-08-29" && time <= "2016-09-09 16:55:30"'
LV CTime
lvol2 2016-09-09 16:55:12 +0200
lvol1 2016-08-29 12:53:36 +0200
lvol0 2016-08-29 10:15:17 +0200
# lvs -o name,time \
-S 'time since "2016-08-29" && time < "2016-09-09 16:55:12"'
LV CTime
lvol1 2016-08-29 12:53:36 +0200
lvol0 2016-08-29 10:15:17 +0200
Example below demonstrates using absolute time expression.
# lvs -o name,time --config report/time_format="%s"
LV CTime
lvol4 1473433064
lvol3 1473433008
lvol2 1473432912
lvol1 1472468016
lvol0 1472458517
# lvs -o name,time -S 'time since @1473433008'
LV CTime
lvol4 2016-09-09 16:57:44 +0200
lvol3 2016-09-09 16:56:48 +0200
Examples below demonstrates using freeform time expressions.
# lvs -o name,time -S 'time since "2 weeks ago"'
LV CTime
lvol4 2016-09-09 16:57:44 +0200
lvol3 2016-09-09 16:56:48 +0200
lvol2 2016-09-09 16:55:12 +0200
lvol1 2016-08-29 12:53:36 +0200
lvol0 2016-08-29 10:15:17 +0200
# lvs -o name,time -S 'time since "1 week ago"'
LV CTime
lvol4 2016-09-09 16:57:44 +0200
lvol3 2016-09-09 16:56:48 +0200
lvol2 2016-09-09 16:55:12 +0200
# lvs -o name,time -S 'time since "2 weeks ago"'
LV CTime
lvol1 2016-08-29 12:53:36 +0200
lvol0 2016-08-29 10:15:17 +0200
# lvs -o name,time -S 'time before "1 week ago"'
LV CTime
lvol1 2016-08-29 12:53:36 +0200
lvol0 2016-08-29 10:15:17 +0200
# lvs -o name,time -S 'time since "68 hours ago"'
LV CTime
lvol4 2016-09-09 16:57:44 +0200
lvol3 2016-09-09 16:56:48 +0200
lvol2 2016-09-09 16:55:12 +0200
# lvs -o name,time -S 'time since "1 year 3 months ago"'
LV CTime
lvol4 2016-09-09 16:57:44 +0200
lvol3 2016-09-09 16:56:48 +0200
lvol2 2016-09-09 16:55:12 +0200
lvol1 2016-08-29 12:53:36 +0200
lvol0 2016-08-29 10:15:17 +0200
Command log reporting
As described in categorization based on reporting facility
section at the beginning of this document, both report-oriented
and processing-oriented LVM commands can report the command log
if this is enabled with log/report_command_log configuration
setting. Just like any other report, we can set the set of
fields to display (log/command_log_cols) and to sort by
(log/command_log_sort) for this report.
# lvmconfig --type full log/report_command_log log/command_log_cols \
log/command_log_sort log/command_log_selection
report_command_log=1
command_log_cols="log_seq_num,log_type,log_context,log_object_type,
log_object_name,log_object_group,log_message,
log_errno,log_ret_code"
command_log_sort="log_seq_num"
command_log_selection="!(log_type=status && message=success)"
# lvs
Logical Volume
==============
LV LSize Cpy%Sync
lvol1 4.00m 100.00
lvol0 4.00m
Command Log
===========
Seq LogType Context ObjType ObjName ObjGrp Msg Errno RetCode
As you can see, the command log is empty (it contains only field
names). By default, LVM uses selection on the command log report
and this case no row matched the selection criteria, see also log
report specifics section in this document for more information.
We're displaying complete log report in the example below where
we can see that both LVs lvol0 and lvol1 were successfully
processed as well as the VG vg they are part of.
# lvmconfig --type full log/command_log_selection
command_log_selection="all"
# lvs
Logical Volume
==============
LV LSize Cpy%Sync
lvol1 4.00m 100.00
lvol0 4.00m
Command Log
===========
Seq LogType Context ObjType ObjName ObjGrp Msg Errno RetCode
1 status processing lv lvol0 vg success 0 1
2 status processing lv lvol1 vg success 0 1
3 status processing vg vg success 0 1
# lvchange -an vg/lvol1
Command Log
===========
Seq LogType Context ObjType ObjName ObjGrp Msg Errno RetCode
1 status processing lv lvol1 vg success 0 1
2 status processing vg vg success 0 1
Handling multiple reports per single command
To configure the log report directly on command line, we need to
use --configreport option before we start any -o|--options,
-O|--sort or -S|--select that is targeted for log report.
# lvs -o lv_name,lv_size --configreport log -o log_object_type, \
log_object_name,log_message,log_ret_code
Logical Volume
==============
LV LSize
lvol1 4.00m
lvol0 4.00m
Command Log
===========
ObjType ObjName Msg RetCode
lv lvol0 success 1
lv lvol1 success 1
vg vg success 1
The lvm fullreport, with or without log report, consists of
several reports - the --configreport is also used to target
particular subreport here.
Below is an extended example with lvm fullreport to illustrate
combination of various options. The report output is in JSON
format. Also, we configure "vg", "pvseg", "seg" and "log"
subreport to contain only specified fields. For the "pvseg"
subreport, we're interested only in PV names having "sda" in
their name. For the "log" subreport we're interested only in log
lines related to either "lvol0" object or object having "sda" in
its name. Also, for the log subreport we define ordering to be
based on "log_object_type" field.
# lvm fullreport --reportformat json \
--configreport vg -o vg_name,vg_size \
--configreport pvseg -o pv_name,pvseg_start \
-S 'pv_name=~sda' \
--configreport seg -o lv_name,seg_start \
--configreport log -o log_object_type,log_object_name \
-O log_object_type \
-S 'log_object_name=lvol0 || \
log_object_name=~sda'
{
"report": [
{
"vg": [
{"vg_name":"vg", "vg_size":"200.00m"}
]
,
"pv": [
{"pv_name":"/dev/sda", "vg_name":"vg"},
{"pv_name":"/dev/sdb", "vg_name":"vg"}
]
,
"lv": [
{"lv_name":"lvol0", "vg_name":"vg"},
{"lv_name":"lvol1", "vg_name":"vg"}
]
,
"pvseg": [
{"pv_name":"/dev/sda", "pvseg_start":"0"},
{"pv_name":"/dev/sda", "pvseg_start":"1"},
{"pv_name":"/dev/sda", "pvseg_start":"2"},
{"pv_name":"/dev/sda", "pvseg_start":"3"}
]
,
"seg": [
{"lv_name":"lvol0", "seg_start":"0 "},
{"lv_name":"lvol1", "seg_start":"0 "}
]
}
]
,
"log": [
{"log_object_type":"lv", "log_object_name":"lvol0"},
{"log_object_type":"lv", "log_object_name":"lvol0"},
{"log_object_type":"pv", "log_object_name":"/dev/sda"},
{"log_object_type":"pv", "log_object_name":"/dev/sda"},
]
}
Report extensions for LVM shell
As already stated in log report coverage paragraph under log
report specifics in this documentation, when using LVM shell the
log report coverage is wider. There's also special command
designed to query last command's log report in the LVM shell -
the lastlog command.
The example below illustrates a situation where we called lvs
command. After that, we inspected the log report with the
lastlog, without any selection so all the log report is displayed
on output. Then we called lastlog further, giving various
selection criteria. Then we ran unknown LVM command "abc" for
which the log report displays appropriate failure state.
# lvm
lvm> lvs
Logical Volume
==============
LV LSize Cpy%Sync
lvol1 4.00m 100.00
lvol0 4.00m
Command Log
===========
Seq LogType Context ObjType ObjName ObjGrp Msg Errno RetCode
1 status processing lv lvol0 vg success 0 1
2 status processing lv lvol1 vg success 0 1
3 status processing vg vg success 0 1
4 status shell cmd lvs success 0 1
lvm> lastlog
Command Log
===========
Seq LogType Context ObjType ObjName ObjGrp Msg Errno RetCode
1 status processing lv lvol0 vg success 0 1
2 status processing lv lvol1 vg success 0 1
3 status processing vg vg success 0 1
4 status shell cmd lvs success 0 1
lvm> lastlog -S log_object_type=lv
Command Log
===========
Seq LogType Context ObjType ObjName ObjGrp Msg Errno RetCode
1 status processing lv lvol0 vg success 0 1
2 status processing lv lvol1 vg success 0 1
lvm> lastlog -S log_context=shell
Command Log
===========
Seq LogType Context ObjType ObjName ObjGrp Msg Errno RetCode
4 status shell cmd lvs success 0 1
lvm> abc
Command Log
===========
Seq LogType Context ObjType ObjName ObjGrp Msg Errno RetCode
1 error shell cmd abc No such command 'abc'. Try 'help'. -1 0
2 status shell cmd abc failure -1 2
