Chapter 7. Customizing the LVM report
Chapter 7. Customizing the LVM report LVM provides a wide range of configuration and command line options to produce customized reports. You can sort the output, specify units, use selection criteria, and update the lvm.conf file to customize the LVM report. 7.1. Controlling the format of the LVM display When you use the pvs , lvs , or vgs command without additional options, you see the default set of fields displayed in the default sort order. The default fields for the pvs command include the following information sorted by the name of physical volumes: PV Physical volume name. VG Volume group name. Fmt Metadata format of the physical volume: lvm2 or lvm1 . Attr Status of the physical volume: (a) - allocatable or (x) - exported. PSize Size of the physical volume. PFree Free space remaining on the physical volume. Displaying custom fields To display a different set of fields than the default, use the -o option. The following example displays only the name, size and free space of the physical volumes: Sorting the LVM display To sort the results by specific criteria, use the -O option. The following example sorts the entries by the free space of their physical volumes in ascending order: To sort the results by descending order, use the -O option along with the - character: Additional resources lvmreport(7) , lvs(8) , vgs(8) , and pvs(8) man pages on your system Specifying the units for an LVM display Customizing the LVM configuration file 7.2. Specifying the units for an LVM display You can view the size of the LVM devices in base 2 or base 10 units by specifying the --units argument of an LVM display command. See the following table for all arguments: Units type Description Available options Default Base 2 units Units are displayed in powers of 2 (multiples of 1024). b : Bytes. s : Sectors, 512 bytes each. k : Kibibytes. m : Mebibytes. g : Gibibytes. t : Tebibytes. p : Pebibytes. e : Exbibytes. h : Human-readable, the most suitable unit is used. r : Human-readable with rounding indicator, works similarly to h with rounding prefix < or > to indicate how LVM rounds the displayed size to the nearest unit. r (when --units is not specified). You can override the default by setting the units parameter in the global section of the /etc/lvm/lvm.conf file. Base 10 units Units are displayed in multiples of 1000. B : Bytes. S : Sectors, 512 bytes each. K : Kilobytes. M : Megabytes. G : Gigabytes. T : Terabytes. P : Petabytes. E : Exabytes. H : Human-readable, the most suitable unit is used. R : Human-readable with rounding indicator, works similarly to H with rounding prefix < or > to indicate how LVM rounds the displayed size to the nearest unit. N/A Custom units Combination of a quantity with a base 2 or base 10 unit. For example, to display the results in 4 mebibytes, use 4m . N/A N/A If you do not specify a value for the units, human-readable format ( r ) is used by default. The following vgs command displays the size of VGs in human-readable format. The most suitable unit is used and the rounding indicator < shows that the actual size is an approximation and it is less than 931 gibibytes. The following pvs command displays the output in base 2 gibibyte units for the /dev/vdb physical volume: The following pvs command displays the output in base 10 gigabyte units for the /dev/vdb physical volume: The following pvs command displays the output in 512-byte sectors: You can specify custom units for an LVM display command. The following example displays the output of the pvs command in units of 4 mebibytes: 7.3. Customizing the LVM configuration file You can customize your LVM configuration according to your specific storage and system requirements by editing the lvm.conf file. For example, you can edit the lvm.conf file to modify filter settings, configure volume group auto activation, manage a thin pool, or automatically extend a snapshot. Procedure: Open the lvm.conf file in an editor of your choice. Customize the lvm.conf file by uncommenting and modifying the setting for which you want to modify the default display values. To customize what fields you see in the lvs output, uncomment the lvs_cols parameter and modify it: To hide empty fields for the pvs , vgs , and lvs commands, uncomment the compact_output=1 setting: To set gigabytes as the default unit for the pvs , vgs , and lvs commands, replace the units = "r" setting with units = "G" : Ensure that the corresponding section of the lvm.conf file is uncommented. For example, to modify the lvs_cols parameter, the report section must be uncommented: Verification View the changed values after modifying the lvm.conf file: Additional resources lvm.conf(5) man page on your system 7.4. Defining LVM selection criteria Selection criteria are a set of statements in the form of <field> <operator> <value> , which use comparison operators to define values for specific fields. Objects that match the selection criteria are then processed or displayed. Objects can be physical volumes (PVs), volume groups (VGs), or logical volumes (LVs). Statements are combined by logical and grouping operators. To define selection criteria use the -S or --select option followed by one or multiple statements. The -S option works by describing the objects to process, rather than naming each object. This is helpful when processing many objects and it would be difficult to find and name each object separately or when searching objects that have a complex set of characteristics. The -S option can also be used as a shortcut to avoid typing many names. To see full sets of fields and possible operators, use the lvs -S help command. Replace lvs with any reporting or processing command to see the details of that command: Reporting commands include pvs , vgs , lvs , pvdisplay , vgdisplay , lvdisplay , and dmsetup info -c . Processing commands include pvchange , vgchange , lvchange , vgimport , vgexport , vgremove , and lvremove . Examples of selection criteria using the pvs commands The following example of the pvs command displays only physical volumes with a name that contains the string nvme : The following example of the pvs command displays only physical devices in the myvg volume group: Examples of selection criteria using the lvs commands The following example of the lvs command displays only logical volumes with a size greater than 100m but less than 200m: The following example of the lvs command displays only logical volumes with a name that contains lvol and any number between 0 and 2: The following example of the lvs command displays only logical volumes with a raid1 segment type: Advanced examples You can combine selection criteria with other options. The following example of the lvchange command adds a specific tag mytag to only active logical volumes: The following example of the lvs command displays all logical volumes whose name does not match _pmspare and changes the default headers to custom ones: The following example of the lvchange command flags a logical volume with role=thinsnapshot and origin=thin1 to be skipped during normal activation commands: The following example of the lvs command displays only logical volumes that match all three conditions: Name contains _tmeta . Role is metadata . Size is less or equal to 4m. Additional resources lvmreport(7) man page on your system
pvs PV VG Fmt Attr PSize PFree /dev/vdb1 VolumeGroupName lvm2 a-- 17.14G 17.14G /dev/vdb2 VolumeGroupName lvm2 a-- 17.14G 17.09G /dev/vdb3 VolumeGroupName lvm2 a-- 17.14G 17.14G pvs -o pv_name,pv_size,pv_free PV PSize PFree /dev/vdb1 17.14G 17.14G /dev/vdb2 17.14G 17.09G /dev/vdb3 17.14G 17.14G pvs -o pv_name,pv_size,pv_free -O pv_free PV PSize PFree /dev/vdb2 17.14G 17.09G /dev/vdb1 17.14G 17.14G /dev/vdb3 17.14G 17.14G pvs -o pv_name,pv_size,pv_free -O -pv_free PV PSize PFree /dev/vdb1 17.14G 17.14G /dev/vdb3 17.14G 17.14G /dev/vdb2 17.14G 17.09G vgs myvg VG #PV #LV #SN Attr VSize VFree myvg 1 1 0 wz-n <931.00g <930.00g pvs --units g /dev/vdb PV VG Fmt Attr PSize PFree /dev/vdb myvg lvm2 a-- 931.00g 930.00g pvs --units G /dev/vdb PV VG Fmt Attr PSize PFree /dev/vdb myvg lvm2 a-- 999.65G 998.58G pvs --units s PV VG Fmt Attr PSize PFree /dev/vdb myvg lvm2 a-- 1952440320S 1950343168S pvs --units 4m PV VG Fmt Attr PSize PFree /dev/vdb myvg lvm2 a-- 238335.00U 238079.00U lvs_cols="lv_name,vg_name,lv_attr" compact_output = 1 units = "G" report { } lvmconfig --typeconfig diff pvs -S name=~nvme PV Fmt Attr PSize PFree /dev/nvme2n1 lvm2 --- 1.00g 1.00g pvs -S vg_name=myvg PV VG Fmt Attr PSize PFree /dev/vdb1 myvg lvm2 a-- 1020.00m 396.00m /dev/vdb2 myvg lvm2 a-- 1020.00m 896.00m lvs -S 'size > 100m && size < 200m' LV VG Attr LSize Cpy%Sync rr myvg rwi-a-r--- 120.00m 100.00 lvs -S name=~lvol[02] LV VG Attr LSize lvol0 myvg -wi-a----- 100.00m lvol2 myvg -wi------- 100.00m lvs -S segtype=raid1 LV VG Attr LSize Cpy%Sync rr myvg rwi-a-r--- 120.00m 100.00 lvchange --addtag mytag -S active=1 Logical volume myvg/mylv changed. Logical volume myvg/lvol0 changed. Logical volume myvg/lvol1 changed. Logical volume myvg/rr changed. lvs -a -o lv_name,vg_name,attr,size,pool_lv,origin,role -S 'name!~_pmspare' LV VG Attr LSize Pool Origin Role thin1 example Vwi-a-tz-- 2.00g tp public,origin,thinorigin thin1s example Vwi---tz-- 2.00g tp thin1 public,snapshot,thinsnapshot thin2 example Vwi-a-tz-- 3.00g tp public tp example twi-aotz-- 1.00g private [tp_tdata] example Twi-ao---- 1.00g private,thin,pool,data [tp_tmeta] example ewi-ao---- 4.00m private,thin,pool,metadata lvchange --setactivationskip n -S 'role=thinsnapshot && origin=thin1' Logical volume myvg/thin1s changed. lvs -a -S 'name=~_tmeta && role=metadata && size <= 4m' LV VG Attr LSize [tp_tmeta] myvg ewi-ao---- 4.00m