View source for Adding a Disk and Extending a Logical Volume

So you have a logical volume that has run out of space and you need to add more.  Either it's a VM and you've added another disk file or it's a physical server and you've added another disk.  

1. Check the current disk devices with the following commands:

  # pvscan
    PV /dev/sdb1   VG data   lvm2 [100.00 GiB / 0    free]
    PV /dev/sdc1    VG data  lvm2 [100.00 GiB / 0    free]
    PV /dev/sda3   VG vg1    lvm2 [47.84 GiB / 17.59 GiB free]
    Total: 4 [247.83 GiB] / in use: 3 [247.83 GiB] / in no VG: 0 [0   ]
  
  # ls -al /dev/sd*
  brw-rw---- 1 root disk 8,  0 Jan 22 01:14 /dev/sda
  brw-rw---- 1 root disk 8,  1 Jan 22 01:14 /dev/sda1
  brw-rw---- 1 root disk 8,  2 Jan 22 01:14 /dev/sda2
  brw-rw---- 1 root disk 8,  3 Jan 22 01:14 /dev/sda3
  brw-rw---- 1 root disk 8, 16 Jan 22 01:14 /dev/sdb
  brw-rw---- 1 root disk 8, 17 Jan 22 01:14 /dev/sdb1
  brw-rw---- 1 root disk 8, 32 Jan 22 01:14 /dev/sdc
  brw-rw---- 1 root disk 8, 33 Jan 22 01:14 /dev/sdc1

2. Scan the scsi bus to find the new disk

List the host SCSI adapters
  # ls /sys/class/scsi_host/
  host0  host1  host2

Probe each host adapter
  # echo "- - -" > /sys/class/scsi_host/host0/scan
  # echo "- - -" > /sys/class/scsi_host/host1/scan
  # echo "- - -" > /sys/class/scsi_host/host2/scan

3. Check to see if the new device is there

  # ls -al /dev/sd*
  brw-rw---- 1 root disk 8,  0 Jan 22 01:14 /dev/sda
  brw-rw---- 1 root disk 8,  1 Jan 22 01:14 /dev/sda1
  brw-rw---- 1 root disk 8,  2 Jan 22 01:14 /dev/sda2
  brw-rw---- 1 root disk 8,  3 Jan 22 01:14 /dev/sda3
  brw-rw---- 1 root disk 8, 16 Jan 22 01:14 /dev/sdb
  brw-rw---- 1 root disk 8, 17 Jan 22 01:14 /dev/sdb1
  brw-rw---- 1 root disk 8, 32 Jan 22 01:14 /dev/sdc
  brw-rw---- 1 root disk 8, 33 Jan 22 01:14 /dev/sdc1
  '''brw-rw---- 1 root disk 8, 48 Jan 22 01:14 /dev/sdd'''

4. Add the disk to your machine as a primary partition

  # fdisk /dev/sdd
  Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
  Building a new DOS disklabel with disk identifier 0x663d32f6.
  Changes will remain in memory only, until you decide to write them.
  After that, of course, the previous content won't be recoverable.
  
  Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
  
  WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
           switch off the mode (command 'c') and change display units to
           sectors (command 'u').
  
  Command (m for help): '''m'''
  Command action
     a   toggle a bootable flag
     b   edit bsd disklabel
     c   toggle the dos compatibility flag
     d   delete a partition
     l   list known partition types
     m   print this menu
     n   add a new partition
     o   create a new empty DOS partition table
     p   print the partition table
     q   quit without saving changes
     s   create a new empty Sun disklabel
     t   change a partition's system id
     u   change display/entry units
     v   verify the partition table
     w   write table to disk and exit
     x   extra functionality (experts only)
  
  Command (m for help): '''n'''
  Command action
     e   extended
     p   primary partition (1-4)
  '''p'''
  Partition number (1-4): '''1'''
  First cylinder (1-13054, default 1):
  Using default value 1
  Last cylinder, +cylinders or +size{K,M,G} (1-13054, default 13054):
  Using default value 13054
  
  Command (m for help): '''w'''
  The partition table has been altered!
  
  Calling ioctl() to re-read partition table.
  Syncing disks.


5.  Create a new physical LVM volume on our new disk.

  # pvcreate /dev/sdd1
    Physical volume "/dev/sdd1" successfully created
  
  You sould now have an additional device:

  # ls -al /dev/sd*
  brw-rw---- 1 root disk 8,  0 Jan 22 01:14 /dev/sda
  brw-rw---- 1 root disk 8,  1 Jan 22 01:14 /dev/sda1
  brw-rw---- 1 root disk 8,  2 Jan 22 01:14 /dev/sda2
  brw-rw---- 1 root disk 8,  3 Jan 22 01:14 /dev/sda3
  brw-rw---- 1 root disk 8, 16 Jan 22 01:14 /dev/sdb
  brw-rw---- 1 root disk 8, 17 Jan 22 01:14 /dev/sdb1
  brw-rw---- 1 root disk 8, 32 Jan 22 01:14 /dev/sdc
  brw-rw---- 1 root disk 8, 33 Jan 22 01:14 /dev/sdc1
  brw-rw---- 1 root disk 8, 48 Jan 22 01:14 /dev/sdd
  '''brw-rw---- 1 root disk 8, 49 Jan 22 01:14 /dev/sdd1'''

6. Extend the Volume Group, in this case called '''data'''

  # vgextend data /dev/sdd1
    Volume group "data" successfully extended

The new disk should now be added to the Volume Group:

  # vgdisplay -v data
      Using volume group(s) on command line
      Finding volume group "data"
    --- Volume group ---
    VG Name               data
    System ID
    Format                lvm2
    Metadata Areas        3
    Metadata Sequence No  11
    VG Access             read/write
    VG Status             resizable
    MAX LV                0
    Cur LV                1
    Open LV               1
    Max PV                0
    Cur PV                3
    Act PV                3
    VG Size               299.99 GiB
    PE Size               4.00 MiB
    Total PE              76797
    Alloc PE / Size       51193 / 199.97 GiB
    Free  PE / Size       25604 / 100.02 GiB
    VG UUID               lEHcjJ-OEEf-pEbi-J00j-5de9-T3ZE-4QPv4H
  
    --- Logical volume ---
    LV Name                /dev/data/blah
    VG Name                data
    LV UUID                aiOIEx-2kK5-RVGr-SHWv-InhH-B69p-j65ziL
    LV Write Access        read/write
    LV Status              available
    # open                 1
    LV Size                199.97 GiB
    Current LE             51193
    Segments               2
    Allocation             inherit
    Read ahead sectors     auto
    - currently set to     256
    Block device           253:1
  
    --- Physical volumes ---
    PV Name               /dev/sdb1
    PV UUID               C0KYU9-krfx-c7pw-pLWo-wf3l-EqiO-qBx3wi
    PV Status             allocatable
    Total PE / Free PE    25599 / 0
  
    PV Name               /dev/sdc1
    PV UUID               qIo3zt-TwBx-Ze6x-BZvy-aY7x-n1NP-IgimVk
    PV Status             allocatable
    Total PE / Free PE    25599 / 5
  
    '''PV Name               /dev/sdd1
    PV UUID               bbUskE-8rDY-CdgP-0tQy-CVrJ-SBZI-kaQmUj
    PV Status             allocatable
    Total PE / Free PE    25599 / 25599'''

7.