This is a bit of a cut'n'paste of a document I wrote for internal use and although it probably over-answers your question I thought I'd put it on here in case it's of use to you or others OK.
Login to the machine as root or sudo each of the following commands, enter fdisk –l, you should see something like this;
Disk /dev/sda: 21.1 GB, 21xxxxxxxxx bytes
255 heads, 63 sectors/track, 5221 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda2 14 2610 20860402+ 8e Linux LVM
In this case I've altered the values but as you can see this machine has a single ~20GB root virtual disk with two partitions, sda1 and sda2, sda2 is our first LVM 'physical volume', see how LVM uses a partition type of '8e'.
Now type pvdisplay, you'll see a section for this first PV (sda2) like this;
--- Physical volume ---
PV Name /dev/sda2
VG Name rootvg
PV Size 19.89 GB / not usable 19.30 MB
Allocatable yes (but full)
PE Size (KByte) 32768
Total PE 636
Free PE 0
Allocated PE 636
PV UUID PgwRdY-EvCC-b5lO-Qrnx-tkrd-m16k-eQ9beC
This shows that this second partition (sda2) is mapped to a 'volume group' called 'rootvg'.
Now we can increase the size of the virtual disk using the usual vSphere VSClient by selecting the VM, choosing to 'edit settings', then selecting 'Hard Disk 1'. You can then increase the 'Provisioned Size' number – so long as there are no snapshots in place anyway – and select OK. This will take a few seconds to complete.
If you then switch back to the Linux VM and enter
echo "- - -" > /sys/class/scsi_host/hostX/scan
where the X character is likely to be zero, it will perform a SCSI bus rescan, then run fdisk –l, you should see something like;
Disk /dev/sda: 42.2 GB, 42xxxxxxxxx bytes
255 heads, 63 sectors/track, 5221 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda2 14 2610 20860402+ 8e Linux LVM
You'll see that the disk size has increased, in this case to ~40GB from ~20GB but that the partition table remains the same.
We now need to create a new LVM partition, type parted, you should see something like this;
GNU Parted 1.8.1
Using /dev/sda
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted)
You'll now need to create a new partition for the extra new space, type 'p' to see the current partition table such as this;
Model: VMware Virtual disk (scsi)
Disk /dev/sda: 42.9GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Number Start End Size Type File system Flags
1 32.3kB 107MB 107MB primary ext3 boot
2 107MB 21.5GB 21.4GB primary lvm
Then type mkpart, then select 'p' for 'Primary', for file system type enter 'ext3', for start enter a number a little higher than the combination of both 'sizes' listed above (i.e. 107MB + 21.4GB, so say 21.6GB), for end type the size of the disk (i.e. in this case 42.9GB). Once you press enter it will create this new primary partition, type 'p' to show the new partition table, you should see something like;
Model: VMware Virtual disk (scsi)
Disk /dev/sda: 42.9GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Number Start End Size Type File system Flags
1 32.3kB 107MB 107MB primary ext3 boot
2 107MB 21.5GB 21.4GB primary lvm
3 21.5GB 42.9GB 21.5GB primary ext3
You'll see that the new partition started after the first two and fills the available space, unfortunately we had to set it to a type of 'ext3', so let's change that.
Type 't', then the partition number (in our case 3 as it's the third partition), then for the 'hex code' enter '8e' – once you'd done this type 'p' again and you should see it change to 'Linux LVM';
Disk /dev/sda: 42.9 GB, 42949672960 bytes
ads, 63 sectors/track, 5221 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda2 14 2610 20860402+ 8e Linux LVM
/dev/sda3 2611 5221 20972857+ 8e Linux LVM
Now we need to create a new LVM 'physical volume' in this new partition, type pvcreate /dev/sda3, this should then create a new LVM PV called /dev/sda3, type pvdisplay to check;
--- Physical volume ---
PV Name /dev/sda3
VG Name
PV Size 20.00 GB / not usable 1.31 MB
Allocatable no
PE Size (KByte) 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID gpYPUv-XdeL-TxKJ-GYCa-iWcy-9bG6-tfZtSh
You should see something similar to above.
Now we need to extend the 'rootvg Volume Group', or create a new one for non-root 'volume group', type vgdisplay to list all 'volume groups', here's an example;
--- Volume group ---
VG Name rootvg
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 19
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 8
Open LV 8
Max PV 0
Cur PV 2
Act PV 2
VG Size 21.3 GB
PE Size 32.00 MB
Total PE 1276
Alloc PE / Size 846 / 26.44 GB
Free PE / Size 430 / 13.44 GB
VG UUID tGM4ja-k6es-la0H-LcX6-1FMY-6p2g-SRYtfY
If you want to extend the 'rootvg Volume Group' type vgextend rootvg /dev/sda3, once you press enter you should see a message saying the 'volume group' has been extended.
If you wanted to create a new 'volume group' you'll need to use the vgcreate command – probably best call me for help with that.
Once extended enter vgdisplay again to see that the 'rootvg' 'volume group' has indeed been extended such as here;
--- Volume group ---
VG Name rootvg
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 19
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 8
Open LV 8
Max PV 0
Cur PV 2
Act PV 2
VG Size 39.88 GB
PE Size 32.00 MB
Total PE 1276
Alloc PE / Size 846 / 26.44 GB
Free PE / Size 430 / 13.44 GB
VG UUID tGM4ja-k6es-la0H-LcX6-1FMY-6p2g-SRYtfY
You can see the 'VG Size' is as expected.
Now we need to extend the 'logical volume', type lvdisplay to show our 'logical volumes', you'll see something like;
--- Logical volume ---
LV Name /dev/rootvg/var
VG Name rootvg
LV UUID NOP1jF-09Xt-LkX5-ai4w-Srqb-xGka-nYbI2J
LV Write Access read/write
LV Status available
# open 1
LV Size 3.00 GB
Current LE 320
Segments 3
Allocation inherit
Read ahead sectors auto
currently set to 256
Block device 253:2
If we want to expand the /var file system from 3GB to 10GB then type lvextend –L 10G /dev/rootvg/var, now type lvdisplay again, you'll see the 'logical volume' has grown to 10GB;
--- Logical volume ---
LV Name /dev/rootvg/var
VG Name rootvg
LV UUID NOP1jF-09Xt-LkX5-ai4w-Srqb-xGka-nYbI2J
LV Write Access read/write
LV Status available
# open 1
LV Size 10.00 GB
Current LE 320
Segments 3
Allocation inherit
Read ahead sectors auto
currently set to 256
Block device 253:2
Now the last thing we need to do is to grow the actual file system, this doesn't have to use all of the newly added space by the way. Enter df –h to show the current filesystems, here's an example;
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/rootvg-root
2.0G 1.4G 495M 74% /
/dev/mapper/rootvg-home
248M 124M 113M 53% /home
/dev/mapper/rootvg-var
3.0G 1.1G 1.8G 30% /var
/dev/mapper/rootvg-usr
3.0G 936M 1.9G 34% /usr
/dev/mapper/rootvg-opt
3.0G 811M 2.0G 29% /opt
If we want to expand the /var file system from 3GB to 10GB then type resize2fs /dev/mapper/rootvg-var (or on CentOS maybe xfs_growfs /dev/mapper/rootvg-var, or similar commands depending on the type of file system). When you press enter the actual filesystem will grow, this may take time, enter df –h once completed to check.
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/rootvg-root
2.0G 1.4G 495M 74% /
/dev/mapper/rootvg-home
248M 124M 113M 53% /home
/dev/mapper/rootvg-var
9.88G 1.1G 8.2G 12% /var
/dev/mapper/rootvg-usr
3.0G 936M 1.9G 34% /usr
/dev/mapper/rootvg-opt
3.0G 811M 2.0G 29% /opt
Best Answer
To bring up the boot menu during POST, press ESC. If it flies by too quick and you miss it, there is an option to delay the boot to give you enough time to hit it. It's under the VM's properties, but I can't remember what the tab is called.
Good luck! Hopefully you aren't running LVM, because that is not as simple to expand/extend.