redhat Linux 7.2: How to increase the size of LUN dynamically

Case: How to increase the size of LUN dynamically ? or Increase size of LUN without Reboot

Procedure:

# fdisk -l | grep Disk

Disk /dev/sdb: 85.9 GB, 85899345920 bytes

Disk identifier: 0x00000000

# echo "1" > /sys/block/sdb/device/rescan

# tail /var/log/messages

Dec  6 13:52:56 kernel: sd 2:0:1:0: [sdb] 209715200 512-byte logical blocks: (107 GB/100 GiB)

Dec  6 13:52:56 kernel: sd 2:0:1:0: [sdb] Cache data unavailable

Dec  6 13:52:56 kernel: sd 2:0:1:0: [sdb] Assuming drive cache: write through

Dec  6 13:52:56 kernel: sdb: detected capacity change from 85899345920 to 107374182400

# fdisk -l | grep -i sdb

Disk /dev/sdb: 107.4 GB, 107374182400 bytes

# vgdisplay -v

   

  --- Volume group ---

  VG Name               hosatname_app_vg

  System ID

  Format                lvm2

  Metadata Areas        1

  Metadata Sequence No  2

  VG Access             read/write

  VG Status             resizable

  MAX LV                0

  Cur LV                1

  Open LV               1

  Max PV                0

  Cur PV                1

  Act PV                1

  VG Size               80.00 GiB

  PE Size               4.00 MiB

  Total PE              20479

  Alloc PE / Size       20224 / 79.00 GiB

  Free  PE / Size       255 / 1020.00 MiB

  VG UUID               AT2vyL-aDzL-tWWQ-sqqb-BAlD-x1oE-Soj7eG

# pvresize -v /dev/sdb

    Using physical volume(s) on command line.

    Wiping cache of LVM-capable devices

    Finding all volume groups.

    Archiving volume group "hostname_app_vg" metadata (seqno 2).

    Resizing volume "/dev/sdb" to 209715200 sectors.

    Resizing physical volume /dev/sdb from 0 to 25599 extents.

    Updating physical volume "/dev/sdb"

    Creating volume group backup "/etc/lvm/backup/hostname_app_vg" (seqno 3).

  Physical volume "/dev/sdb" changed

  1 physical volume(s) resized / 0 physical volume(s) not resized

# vgdisplay -v

    Using volume group(s) on command line.

    Finding all volume groups.

  --- Volume group ---

  VG Name               hostname_app_vg

  System ID

  Format                lvm2

  Metadata Areas        1

  Metadata Sequence No  3

  VG Access             read/write

  VG Status             resizable

  MAX LV                0

  Cur LV                1

  Open LV               1

  Max PV                0

  Cur PV                1

  Act PV                1

  VG Size               100.00 GiB

  PE Size               4.00 MiB

  Total PE              25599

  Alloc PE / Size       20224 / 79.00 GiB

  Free  PE / Size       5375 / 21.00 GiB

  VG UUID               AT2vyL-aDzL-tWWQ-sqqb-BAlD-x1oE-Soj7eG

 

# vgs

  VG              #PV #LV #SN Attr   VSize   VFree

  hostname_app_vg   1   1   0 wz--n- 100.00g 21.00g

  hostname_vg       1   9   0 wz--n-  48.97g  6.09g

#lvextend -L +2G /dev/<vgname>/<lvname>

#vgdisplay -v

#resize2fs –p /dev/<vgname>/<lvname>

#df –h