Adding a Disk and Extending a Logical Volume
From Peter Pap's Technowiki
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.
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
