Rocky_Linux_8
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LVM : Manage Logical Volumes
2021/07/20
 
This is the basic operation of managing Logical Volumes.
It needs to create Volume Groups first.
[1] Create Logical Volumes.
# create logical volume [lv_data] in volume group [vg_dlp] with [30G]

[root@dlp ~]#
lvcreate -L 30G -n lv_data vg_dlp

  Logical volume "lv_data" created.

# specify like follows if you use all free area

[root@dlp ~]#
lvcreate -l 100%FREE -n lv_data vg_dlp

  Logical volume "lv_data" created
[2] Display Logical Volumes.
[root@dlp ~]#
lvdisplay /dev/vg_dlp/lv_data

--- Logical volume ---
  LV Path                /dev/vg_dlp/lv_data
  LV Name                lv_data
  VG Name                vg_dlp
  LV UUID                MENDuy-R03g-JORx-OHXi-0Hes-Fw6u-WWuupS
  LV Write Access        read/write
  LV Creation host, time dlp.srv.world, 2021-07-20 19:57:32 +0900
  LV Status              available
  # open                 0
  LV Size                30.00 GiB
  Current LE             7680
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:2
[3] Rename Logical Volume.
# rename from [lv_data] to [lv_storage]

[root@dlp ~]#
lvrename vg_dlp lv_data lv_storage

  Renamed "lv_data" to "lv_storage" in volume group "vg_dlp"

[root@dlp ~]#
lvdisplay /dev/vg_dlp/lv_storage

  --- Logical volume ---
  LV Path                /dev/vg_dlp/lv_storage
  LV Name                lv_storage
  VG Name                vg_dlp
  LV UUID                MENDuy-R03g-JORx-OHXi-0Hes-Fw6u-WWuupS
  LV Write Access        read/write
  LV Creation host, time dlp.srv.world, 2021-07-20 19:57:32 +0900
  LV Status              available
  # open                 0
  LV Size                30.00 GiB
  Current LE             7680
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:2
[4] Display reports of Logical Volumes.
[root@dlp ~]#
lvs

  LV         VG     Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  root       rl     -wi-ao---- <26.00g
  swap       rl     -wi-ao----   3.00g
  lv_storage vg_dlp -wi-a-----  30.00g
[5] Scan Logical Volumes.
[root@dlp ~]#
lvscan

  ACTIVE            '/dev/vg_dlp/lv_storage' [30.00 GiB] inherit
  ACTIVE            '/dev/rl/swap' [3.00 GiB] inherit
  ACTIVE            '/dev/rl/root' [<26.00 GiB] inherit
[6] Take snapshot of Logical Volume.
# create snapshot [snap-lv_storage] from [lv_storage]

[root@dlp ~]#
lvcreate -s -L 30G -n snap-lv_storage /dev/vg_dlp/lv_storage

  Logical volume "snap-lv_storage" created.

[root@dlp ~]#
lvdisplay /dev/vg_dlp/lv_storage /dev/vg_dlp/snap-lv_storage

  --- Logical volume ---
  LV Path                /dev/vg_dlp/lv_storage
  LV Name                lv_storage
  VG Name                vg_dlp
  LV UUID                MENDuy-R03g-JORx-OHXi-0Hes-Fw6u-WWuupS
  LV Write Access        read/write
  LV Creation host, time dlp.srv.world, 2021-07-20 19:57:32 +0900
  LV snapshot status     source of
                         snap-lv_storage [active]
  LV Status              available
  # open                 0
  LV Size                30.00 GiB
  Current LE             7680
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:2

  --- Logical volume ---
  LV Path                /dev/vg_dlp/snap-lv_storage
  LV Name                snap-lv_storage
  VG Name                vg_dlp
  LV UUID                hSJzFn-k6SN-FPAI-oLds-kszt-Rsgy-8gPDw7
  LV Write Access        read/write
  LV Creation host, time dlp.srv.world, 2021-07-20 19:59:41 +0900
  LV snapshot status     active destination for lv_storage
  LV Status              available
  # open                 0
  LV Size                30.00 GiB
  Current LE             7680
  COW-table size         30.00 GiB
  COW-table LE           7680
  Allocated to snapshot  0.00%
  Snapshot chunk size    4.00 KiB
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:5
[7] Extend Logical Volume. It's possible to do with mounted state.
[root@dlp ~]#
lvextend -L 50G /dev/vg_dlp/lv_storage

  Size of logical volume vg_dlp/lv_storage changed from 30.00 GiB (7680 extents) to 50.00 GiB (12800 extents).
  Logical volume vg_dlp/lv_storage successfully resized.

[root@dlp ~]#
lvdisplay /dev/vg_dlp/lv_storage

  --- Logical volume ---
  LV Path                /dev/vg_dlp/lv_storage
  LV Name                lv_storage
  VG Name                vg_dlp
  LV UUID                MENDuy-R03g-JORx-OHXi-0Hes-Fw6u-WWuupS
  LV Write Access        read/write
  LV Creation host, time dlp.srv.world, 2021-07-20 19:57:32 +0900
  LV Status              available
  # open                 0
  LV Size                50.00 GiB
  Current LE             12800
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:2

# if filesystem exists, extend it (specify mount point)

# for the case of [xfs] filesystem

[root@dlp ~]#
xfs_growfs /mnt

meta-data=/dev/mapper/vg_dlp-lv_storage isize=512    agcount=4, agsize=1966080 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=1, sparse=1, rmapbt=0
         =                       reflink=1
data     =                       bsize=4096   blocks=7864320, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0, ftype=1
log      =internal log           bsize=4096   blocks=3840, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 7864320 to 13107200
[8] Reduce Logical Volume. Unmount target device first.
If [xfs] filesystem exists on the target Logical Volume, it's impossible to reduce [xfs] filesystem.
# for [ext4] filesystem, check filesystem before reduce

[root@dlp ~]#
e2fsck -f /dev/vg_dlp/lv_storage

e2fsck 1.44.6 (5-Mar-2019)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/vg_dlp/lv_storage: 11/3276800 files (0.0% non-contiguous), 284558/13107200 blocks

# for [ext4] filesystem, possible to reduce

[root@dlp ~]#
resize2fs /dev/vg_dlp/lv_storage 30G

resize2fs 1.44.6 (5-Mar-2019)
Resizing the filesystem on /dev/vg_dlp/lv_storage to 7864320 (4k) blocks.
The filesystem on /dev/vg_dlp/lv_storage is now 7864320 (4k) blocks long.

# reduce logical volume

[root@dlp ~]#
lvreduce -L 30G /dev/vg_dlp/lv_storage

  WARNING: Reducing active logical volume to 30.00 GiB.
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce vg_dlp/lv_storage? [y/n]: y
  Size of logical volume vg_dlp/lv_storage changed from 50.00 GiB (12800 extents) to 30.00 GiB (7680 extents).
  Logical volume vg_dlp/lv_storage successfully resized.
[9] Delete Logical Volume.
unmount ⇒ stop logical volume ⇒ delete logical volume
[root@dlp ~]#
lvchange -an /dev/vg_dlp/lv_storage

[root@dlp ~]#
lvremove /dev/vg_dlp/lv_storage

  Logical volume "lv_storage" successfully removed
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