4.9.2. Object Selection
This section provides a series of tables that list the information you can display about the LVM objects with the pvs, vgs, and lvs commands.
For convenience, a field name prefix can be dropped if it matches the default for the command. For example, with the pvs command, name means pv_name, but with the vgs command, name is interpreted as vg_name.
Executing the following command is the equivalent of executing pvs -o pv_free.
# pvs -o free PFree 17.14G 17.09G 17.14G
Table 4.1, “pvs Display Fields” lists the display arguments of the pvs command, along with the field name as it appears in the header display and a description of the field.
| Argument | Header | Description |
|---|---|---|
| dev_size | DevSize | The size of the underlying device on which the physical volume was created |
| pe_start | 1st PE | Offset to the start of the first physical extent in the underlying device |
| pv_attr | Attr | Status of the physical volume: (a)llocatable or e(x)ported. |
| pv_fmt | Fmt | The metadata format of the physical volume (lvm2 or lvm1) |
| pv_free | PFree | The free space remaining on the physical volume |
| pv_name | PV | The physical volume name |
| pv_pe_alloc_count | Alloc | Number of used physical extents |
| pv_pe_count | PE | Number of physical extents |
| pvseg_size | SSize | The segment size of the physical volume |
| pvseg_start | Start | The starting physical extent of the physical volume segment |
| pv_size | PSize | The size of the physical volume |
| pv_tags | PV Tags | LVM tags attached to the physical volume |
| pv_used | Used | The amount of space currently used on the physical volume |
| pv_uuid | PV UUID | The UUID of the physical volume |
Table 4.1. pvs Display Fields
The pvs command displays the following fields by default: pv_name, vg_name, pv_fmt, pv_attr, pv_size, pv_free. The display is sorted by pv_name.
# pvs PV VG Fmt Attr PSize PFree /dev/sdb1 new_vg lvm2 a- 17.14G 17.14G /dev/sdc1 new_vg lvm2 a- 17.14G 17.09G /dev/sdd1 new_vg lvm2 a- 17.14G 17.13G
Using the -v argument with the pvs command adds the following fields to the default display: dev_size, pv_uuid.
# pvs -v
Scanning for physical volume names
PV VG Fmt Attr PSize PFree DevSize PV UUID
/dev/sdb1 new_vg lvm2 a- 17.14G 17.14G 17.14G onFF2w-1fLC-ughJ-D9eB-M7iv-6XqA-dqGeXY
/dev/sdc1 new_vg lvm2 a- 17.14G 17.09G 17.14G Joqlch-yWSj-kuEn-IdwM-01S9-XO8M-mcpsVe
/dev/sdd1 new_vg lvm2 a- 17.14G 17.13G 17.14G yvfvZK-Cf31-j75k-dECm-0RZ3-0dGW-tUqkCS
You can use the --segments argument of the pvs command to display information about each physical volume segment. A segment is a group of extents. A segment view can be useful if you want to see whether your logical volume is fragmented.
The pvs --segments command displays the following fields by default: pv_name, vg_name, pv_fmt, pv_attr, pv_size, pv_free, pvseg_start, pvseg_size. The display is sorted by pv_name and pvseg_size within the physical volume.
# pvs --segments PV VG Fmt Attr PSize PFree Start SSize /dev/hda2 VolGroup00 lvm2 a- 37.16G 32.00M 0 1172 /dev/hda2 VolGroup00 lvm2 a- 37.16G 32.00M 1172 16 /dev/hda2 VolGroup00 lvm2 a- 37.16G 32.00M 1188 1 /dev/sda1 vg lvm2 a- 17.14G 16.75G 0 26 /dev/sda1 vg lvm2 a- 17.14G 16.75G 26 24 /dev/sda1 vg lvm2 a- 17.14G 16.75G 50 26 /dev/sda1 vg lvm2 a- 17.14G 16.75G 76 24 /dev/sda1 vg lvm2 a- 17.14G 16.75G 100 26 /dev/sda1 vg lvm2 a- 17.14G 16.75G 126 24 /dev/sda1 vg lvm2 a- 17.14G 16.75G 150 22 /dev/sda1 vg lvm2 a- 17.14G 16.75G 172 4217 /dev/sdb1 vg lvm2 a- 17.14G 17.14G 0 4389 /dev/sdc1 vg lvm2 a- 17.14G 17.14G 0 4389 /dev/sdd1 vg lvm2 a- 17.14G 17.14G 0 4389 /dev/sde1 vg lvm2 a- 17.14G 17.14G 0 4389 /dev/sdf1 vg lvm2 a- 17.14G 17.14G 0 4389 /dev/sdg1 vg lvm2 a- 17.14G 17.14G 0 4389
You can use the pvs -a command to see devices detected by LVM that have not been initialized as LVM physical volumes.
# pvs -a PV VG Fmt Attr PSize PFree /dev/VolGroup00/LogVol01 -- 0 0 /dev/new_vg/lvol0 -- 0 0 /dev/ram -- 0 0 /dev/ram0 -- 0 0 /dev/ram2 -- 0 0 /dev/ram3 -- 0 0 /dev/ram4 -- 0 0 /dev/ram5 -- 0 0 /dev/ram6 -- 0 0 /dev/root -- 0 0 /dev/sda -- 0 0 /dev/sdb -- 0 0 /dev/sdb1 new_vg lvm2 a- 17.14G 17.14G /dev/sdc -- 0 0 /dev/sdc1 new_vg lvm2 a- 17.14G 17.09G /dev/sdd -- 0 0 /dev/sdd1 new_vg lvm2 a- 17.14G 17.14G
Table 4.2, “vgs Display Fields” lists the display arguments of the vgs command, along with the field name as it appears in the header display and a description of the field.
| Argument | Header | Description |
|---|---|---|
| lv_count | #LV | The number of logical volumes the volume group contains |
| max_lv | MaxLV | The maximum number of logical volumes allowed in the volume group (0 if unlimited) |
| max_pv | MaxPV | The maximum number of physical volumes allowed in the volume group (0 if unlimited) |
| pv_count | #PV | The number of physical volumes that define the volume group |
| snap_count | #SN | The number of snapshots the volume group contains |
| vg_attr | Attr | Status of the volume group: (w)riteable, (r)eadonly, resi(z)eable, e(x)ported, (p)artial and (c)lustered. |
| vg_extent_count | #Ext | The number of physical extents in the volume group |
| vg_extent_size | Ext | The size of the physical extents in the volume group |
| vg_fmt | Fmt | The metadata format of the volume group (lvm2 or lvm1) |
| vg_free | VFree | Size of the free space remaining in the volume group |
| vg_free_count | Free | Number of free physical extents in the volume group |
| vg_name | VG | The volume group name |
| vg_seqno | Seq | Number representing the revision of the volume group |
| vg_size | VSize | The size of the volume group |
| vg_sysid | SYS ID | LVM1 System ID |
| vg_tags | VG Tags | LVM tags attached to the volume group |
| vg_uuid | VG UUID | The UUID of the volume group |
Table 4.2. vgs Display Fields
The vgs command displays the following fields by default: vg_name, pv_count, lv_count, snap_count, vg_attr, vg_size, vg_free. The display is sorted by vg_name.
# vgs VG #PV #LV #SN Attr VSize VFree new_vg 3 1 1 wz--n- 51.42G 51.36G
Using the -v argument with the vgs command adds the following fields to the default display: vg_extent_size, vg_uuid.
# vgs -v
Finding all volume groups
Finding volume group "new_vg"
VG Attr Ext #PV #LV #SN VSize VFree VG UUID
new_vg wz--n- 4.00M 3 1 1 51.42G 51.36G jxQJ0a-ZKk0-OpMO-0118-nlwO-wwqd-fD5D32
Table 4.3, “lvs Display Fields” lists the display arguments of the lvs command, along with the field name as it appears in the header display and a description of the field.
| Argument | Header | Description | ||||||
|---|---|---|---|---|---|---|---|---|
|
Chunk | Unit size in a snapshot volume | ||||||
| copy_percent | Copy% | The synchronization percentage of a mirrored logical volume; also used when physical extents are being moved with the pv_move command | ||||||
| devices | Devices | The underlying devices that make up the logical volume: the physical volumes, logical volumes, and start physical extents and logical extents | ||||||
| lv_attr | Attr |
The status of the logical volume. The logical volume attribute bits are as follows:
|
||||||
| lv_kernel_major | KMaj | Actual major device number of the logical volume (-1 if inactive) | ||||||
| lv_kernel_minor | KMIN | Actual minor device number of the logical volume (-1 if inactive) | ||||||
| lv_major | Maj | The persistent major device number of the logical volume (-1 if not specified) | ||||||
| lv_minor | Min | The persistent minor device number of the logical volume (-1 if not specified) | ||||||
| lv_name | LV | The name of the logical volume | ||||||
| lv_size | LSize | The size of the logical volume | ||||||
| lv_tags | LV Tags | LVM tags attached to the logical volume | ||||||
| lv_uuid | LV UUID | The UUID of the logical volume. | ||||||
| mirror_log | Log | Device on which the mirror log resides | ||||||
| modules | Modules | Corresponding kernel device-mapper target necessary to use this logical volume | ||||||
| move_pv | Move | Source physical volume of a temporary logical volume created with the pvmove command | ||||||
| origin | Origin | The origin device of a snapshot volume | ||||||
|
Region | The unit size of a mirrored logical volume | ||||||
| seg_count | #Seg | The number of segments in the logical volume | ||||||
| seg_size | SSize | The size of the segments in the logical volume | ||||||
| seg_start | Start | Offset of the segment in the logical volume | ||||||
| seg_tags | Seg Tags | LVM tags attached to the segments of the logical volume | ||||||
| segtype | Type | The segment type of a logical volume (for example: mirror, striped, linear) | ||||||
| snap_percent | Snap% | Current percentage of a snapshot volume that is in use | ||||||
| stripes | #Str | Number of stripes or mirrors in a logical volume | ||||||
|
Stripe | Unit size of the stripe in a striped logical volume |
Table 4.3. lvs Display Fields
The lvs command displays the following fields by default: lv_name, vg_name, lv_attr, lv_size, origin, snap_percent, move_pv, mirror_log, copy_percent. The default display is sorted by vg_name and lv_name within the volume group.
# lvs LV VG Attr LSize Origin Snap% Move Log Copy% lvol0 new_vg owi-a- 52.00M newvgsnap1 new_vg swi-a- 8.00M lvol0 0.20
Using the -v argauament with the lvs command adds the following fields to the default display: seg_count, lv_major, lv_minor, lv_kernel_major, lv_kernel_minor, lv_uuid.
# lvs -v
Finding all logical volumes
LV VG #Seg Attr LSize Maj Min KMaj KMin Origin Snap% Move Copy% Log LV UUID
lvol0 new_vg 1 owi-a- 52.00M -1 -1 253 3 LBy1Tz-sr23-OjsI-LT03-nHLC-y8XW-EhCl78
newvgsnap1 new_vg 1 swi-a- 8.00M -1 -1 253 5 lvol0 0.20 1ye1OU-1cIu-o79k-20h2-ZGF0-qCJm-CfbsIx
You can use the --segments argument of the lvs command to display information with default columns that emphasize the segment information. When you use the segments argument, the seg prefix is optional. The lvs --segments command displays the following fields by default: lv_name, vg_name, lv_attr, stripes, segtype, seg_size. The default display is sorted by vg_name, lv_name within the volume group, and seg_start within the logical volume. If the logical volumes were fragmented, the output from this command would show that.
# lvs --segments LV VG Attr #Str Type SSize LogVol00 VolGroup00 -wi-ao 1 linear 36.62G LogVol01 VolGroup00 -wi-ao 1 linear 512.00M lv vg -wi-a- 1 linear 104.00M lv vg -wi-a- 1 linear 104.00M lv vg -wi-a- 1 linear 104.00M lv vg -wi-a- 1 linear 88.00M
Using the -v argument with the lvs --segments command adds the following fields to the default display: seg_start, stripesize, chunksize.
# lvs -v --segments
Finding all logical volumes
LV VG Attr Start SSize #Str Type Stripe Chunk
lvol0 new_vg owi-a- 0 52.00M 1 linear 0 0
newvgsnap1 new_vg swi-a- 0 8.00M 1 linear 0 8.00K
The following example shows the default output of the lvs command on a system with one logical volume configured, followed by the default output of the lvs command with the segments argument specified.
# lvs LV VG Attr LSize Origin Snap% Move Log Copy% lvol0 new_vg -wi-a- 52.00M # lvs --segments LV VG Attr #Str Type SSize lvol0 new_vg -wi-a- 1 linear 52.00M