Expanding LVM Partitions in VMware, on the fly

In my previous post on the subject, I expanded Filesystems on LVM without rebooting, by adding more partitions. As pointed out by Zanchey, there is a much cleaner way to do this, by just resizing existing partitions being used by LVM.

# fdisk /dev/sda


The number of cylinders for this disk is set to 9790.

There is nothing wrong with that, but this is larger than 1024,

and could in certain setups cause problems with:

1) software that runs at boot time (e.g., old versions of LILO)

2) booting and partitioning software from other OSs

   (e.g., DOS FDISK, OS/2 FDISK)
Command (m for help): p
Disk /dev/sda: 80.5 GB, 80530636800 bytes

255 heads, 63 sectors/track, 9790 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes
   Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *           1          14      104391   83  Linux

Partition 1 does not end on cylinder boundary.

/dev/sda2              14        4178    33450007+  8e  Linux LVM

/dev/sda3            4178        8354    33549073+  8e  Linux LVM

/dev/sda4            8355        9137     6289447+  8e  Linux LVM
Command (m for help): q
###

### Extend the VMDK in vCenter

###
# fdisk /dev/sda
The number of cylinders for this disk is set to 9790.

There is nothing wrong with that, but this is larger than 1024,

and could in certain setups cause problems with:

1) software that runs at boot time (e.g., old versions of LILO)

2) booting and partitioning software from other OSs

   (e.g., DOS FDISK, OS/2 FDISK)
Command (m for help): p
Disk /dev/sda: 80.5 GB, 80530636800 bytes

255 heads, 63 sectors/track, 9790 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes
   Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *           1          14      104391   83  Linux

Partition 1 does not end on cylinder boundary.

/dev/sda2              14        4178    33450007+  8e  Linux LVM

/dev/sda3            4178        8354    33549073+  8e  Linux LVM

/dev/sda4            8355        9137     6289447+  8e  Linux LVM
Command (m for help): q
###

### Whuuuuuut? I can't see the extra space!

###
# echo '1' > /sys/class/scsi_disk/0\:0\:0\:0/device/rescan
###

### Rescan device geometry

###
# fdisk /dev/sda
The number of cylinders for this disk is set to 11096.

There is nothing wrong with that, but this is larger than 1024,

and could in certain setups cause problems with:

1) software that runs at boot time (e.g., old versions of LILO)

2) booting and partitioning software from other OSs

   (e.g., DOS FDISK, OS/2 FDISK)
Command (m for help): p
Disk /dev/sda: 91.2 GB, 91268055040 bytes

255 heads, 63 sectors/track, 11096 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes
   Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *           1          14      104391   83  Linux

Partition 1 does not end on cylinder boundary.

/dev/sda2              14        4178    33450007+  8e  Linux LVM

/dev/sda3            4178        8354    33549073+  8e  Linux LVM

/dev/sda4            8355        9137     6289447+  8e  Linux LVM
###

### Ok, that's much better.

###
Command (m for help): d

Partition number (1-4): 4
###

### Delete partition 4

###
Command (m for help): n

Command action

   e   extended

   p   primary partition (1-4)

p

Selected partition 4
###

### Now recreate it, so it starts in the same place, and ends at the end of the disk

###
First cylinder (8355-11096, default 8355):

Using default value 8355

Last cylinder or +size or +sizeM or +sizeK (8355-11096, default 11096):

Using default value 11096
Command (m for help): t

Partition number (1-4): 4

Hex code (type L to list codes): 8e

Changed system type of partition 4 to 8e (Linux LVM)
###

### Remember to change the partition type of Linux LVM. Or you'll be in trouble.

###
Command (m for help): p
Disk /dev/sda: 91.2 GB, 91268055040 bytes

255 heads, 63 sectors/track, 11096 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes
   Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *           1          14      104391   83  Linux

Partition 1 does not end on cylinder boundary.

/dev/sda2              14        4178    33450007+  8e  Linux LVM

/dev/sda3            4178        8354    33549073+  8e  Linux LVM

/dev/sda4            8355       11096    22025115   8e  Linux LVM
Command (m for help): w

The partition table has been altered!
###

### Write to disk and away we go

###
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.

The kernel still uses the old table.

The new table will be used at the next reboot.

Syncing disks.

# partprobe -s

/dev/sda: msdos partitions 1 2 3 4
###

### Reprobe partition table

###
# pvresize /dev/sda4

  Physical volume "/dev/sda4" changed

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

### Resize the "filesystem" of the LVM partition we've just extended in fdisk,

### Think of this kind of like resize2fs for LVM, but we'll still have to do that on the logical disks later

###  
# vgdisplay

  --- Volume group ---

  VG Name               VGroot

  System ID

  Format                lvm2

  Metadata Areas        3

  Metadata Sequence No  8

  VG Access             read/write

  VG Status             resizable

  MAX LV                0

  Cur LV                3

  Open LV               2

  Max PV                0

  Cur PV                3

  Act PV                3

  VG Size               84.84 GB

  PE Size               32.00 MB

  Total PE              2715

  Alloc PE / Size       1660 / 51.88 GB

  Free  PE / Size       1055 / 32.97 GB

  VG UUID               tSuI0o-Z3mu-mldY-n4pS-qfSZ-g5UP-tXPZlR
###

### Confirm we can now see the extra space in the LVM group

###
# lvdisplay

  --- Logical volume ---

  LV Name                /dev/VGroot/LVroot

  VG Name                VGroot

  LV UUID                HYQp9x-yA5H-RLJw-f033-pmEY-Lohg-loRhXa

  LV Write Access        read/write

  LV Status              available

  # open                 1

  LV Size                7.88 GB

  Current LE             252

  Segments               1

  Allocation             inherit

  Read ahead sectors     auto

  - currently set to     256

  Block device           253:0
  --- Logical volume ---

  LV Name                /dev/VGroot/LVswap

  VG Name                VGroot

  LV UUID                ZXCxs3-nZd4-jR5S-mkCf-zTJP-yVgp-dpq7Mg

  LV Write Access        read/write

  LV Status              available

  # open                 1

  LV Size                4.00 GB

  Current LE             128

  Segments               1

  Allocation             inherit

  Read ahead sectors     auto

  - currently set to     256

  Block device           253:1
  --- Logical volume ---

  LV Name                /dev/VGroot/LVut01

  VG Name                VGroot

  LV UUID                VUv17I-QbdC-pkyr-bE25-f4MC-gLXq-2QKGr0

  LV Write Access        read/write

  LV Status              available

  # open                 1

  LV Size                40.00 GB

  Current LE             1280

  Segments               2

  Allocation             inherit

  Read ahead sectors     auto

  - currently set to     256

  Block device           253:2
###

### Confirm how big our logical volumes are within our LVM pool

###
# df -h

Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/VGroot-LVroot

                      7.7G  3.3G  4.0G  45% /

/dev/sda1              99M   24M   71M  26% /boot

tmpfs                1014M     0 1014M   0% /dev/shm

/dev/mapper/VGroot-LVut01

                       40G  177M   38G   1% /ut01
###

### Confirm amount of space seen on filesystems within the LVM Logical Volumes

###
# lvextend -L+5G /dev/VGroot/LVut01

  Extending logical volume LVut01 to 45.00 GB

  Logical volume LVut01 successfully resized
###

### Added 5Gb onto our Logical Volume, LVut01

###
# lvdisplay

  --- Logical volume ---

  LV Name                /dev/VGroot/LVroot

  VG Name                VGroot

  LV UUID                HYQp9x-yA5H-RLJw-f033-pmEY-Lohg-loRhXa

  LV Write Access        read/write

  LV Status              available

  # open                 1

  LV Size                7.88 GB

  Current LE             252

  Segments               1

  Allocation             inherit

  Read ahead sectors     auto

  - currently set to     256

  Block device           253:0
  --- Logical volume ---

  LV Name                /dev/VGroot/LVswap

  VG Name                VGroot

  LV UUID                ZXCxs3-nZd4-jR5S-mkCf-zTJP-yVgp-dpq7Mg

  LV Write Access        read/write

  LV Status              available

  # open                 1

  LV Size                4.00 GB

  Current LE             128

  Segments               1

  Allocation             inherit

  Read ahead sectors     auto

  - currently set to     256

  Block device           253:1
  --- Logical volume ---

  LV Name                /dev/VGroot/LVut01

  VG Name                VGroot

  LV UUID                VUv17I-QbdC-pkyr-bE25-f4MC-gLXq-2QKGr0

  LV Write Access        read/write

  LV Status              available

  # open                 1

  LV Size                45.00 GB

  Current LE             1440

  Segments               2

  Allocation             inherit

  Read ahead sectors     auto

  - currently set to     256

  Block device           253:2
# df -h

Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/VGroot-LVroot

                      7.7G  3.3G  4.0G  45% /

/dev/sda1              99M   24M   71M  26% /boot

tmpfs                1014M     0 1014M   0% /dev/shm

/dev/mapper/VGroot-LVut01

                       40G  177M   38G   1% /ut01
###

### So the space is added to the Logical Volume, but the filesystem in the logical volume is not extended

###
# resize2fs /dev/VGroot/LVut01

resize2fs 1.39 (29-May-2006)

Filesystem at /dev/VGroot/LVut01 is mounted on /ut01; on-line resizing required

Performing an on-line resize of /dev/VGroot/LVut01 to 11796480 (4k) blocks.

The filesystem on /dev/VGroot/LVut01 is now 11796480 blocks long.
# df -h

Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/VGroot-LVroot

                      7.7G  3.3G  4.0G  45% /

/dev/sda1              99M   24M   71M  26% /boot

tmpfs                1014M     0 1014M   0% /dev/shm

/dev/mapper/VGroot-LVut01

                       45G  181M   42G   1% /ut01

### ### TADA! All done. ###

This will also work if your root filesystems (“/”) is on LVM, since most of the important stuff is loaded into memory.

4 thoughts on “Expanding LVM Partitions in VMware, on the fly”

Pingback: theducks.org » Blog Archive » Expanding LVM on Boot disk under VMWare 3.5 without rebooting
dionrowney says:

2011-07-19 at 4:23 pm

I tried this but had problems with lvm recognizing the free space after the new partition was created.

I had to reboot instead of running ‘partprobe -s’ as I was getting this:
partprobe -s

Warning: WARNING: the kernel failed to re-read the partition table on /dev/sda (Device or resource busy). As a result, it may not reflect all of your changes until after reboot.

Luckily system was okay to reboot, but it would be nice to be able to do this on a running machine. After that the procedure was good.

I am guessing it was because it was the vg with the root filesystem on it?
alex says:

2011-07-27 at 6:50 am

Yeah, it looks likes that’s the case.
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Expanding LVM Partitions in VMware, on the fly

4 thoughts on “Expanding LVM Partitions in VMware, on the fly”

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