lvmreport

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

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.

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

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.

If you need to select only specific rows from report, you can use LVM's report selection feature. If you call <lvm_command> -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 demostrate 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 

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

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 intested only in PV names having "sda" in their name. For the "log" subreport we're intested 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"},
      ]
  }

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