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.
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. Extend the Logical Volume, in this example by 50Gb
# lvextend -L +50Gb /dev/data/blah Extending logical volume blah to 249.97 GiB Logical volume splunk successfully resized
8. Resize the Logical Volume to start using the new space
# resize2fs -p /dev/data/blah resize2fs 1.41.12 (17-May-2010) Filesystem at /dev/data/blah is mounted on /data; on-line resizing required old desc_blocks = 13, new_desc_blocks = 16 Performing an on-line resize of /dev/data/blah to 65528832 (4k) blocks. The filesystem on /dev/data/blah is now 65528832 blocks long.
9. Check to see it worked
# 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 12
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 63993 / 249.97 GiB
Free PE / Size 12804 / 50.02 GiB
VG UUID lEHcjJ-OEEf-pEbi-J00j-5de9-T3ZE-4QPv4H
--- Logical volume ---
LV Name /dev/data/splunk
VG Name data
LV UUID aiOIEx-2kK5-RVGr-SHWv-InhH-B69p-j65ziL
LV Write Access read/write
LV Status available
# open 1
LV Size 249.97 GiB
Current LE 63993
Segments 3
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 / 0
PV Name /dev/sdd1
PV UUID bbUskE-8rDY-CdgP-0tQy-CVrJ-SBZI-kaQmUj
PV Status allocatable
Total PE / Free PE 25599 / 12804
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg1-root 1008M 209M 749M 22% /
tmpfs 1.9G 0 1.9G 0% /dev/shm
/dev/mapper/vg1-app 25G 5.0G 19G 22% /app
/dev/sda1 124M 31M 88M 26% /boot
/dev/mapper/vg1-home 1008M 114M 844M 12% /home
/dev/mapper/vg1-tmp 756M 17M 701M 3% /tmp
/dev/mapper/vg1-usr 1.5G 1.1G 389M 73% /usr
/dev/mapper/vg1-var 2.0G 412M 1.5G 22% /var
/dev/mapper/data
247G 186G 49G 80% /data
You're done!
