Extend a Linux LVM Volume on a VM - Part 1

As I mentioned in the recent Linux LVM post, there are two ways to prepare the physical volume (PV)

• the entire disk as a PV (not recommended)
• or creating a partition on the disk and the partition as a PV.

The step to extend a LVM volume are different on these two configuration.

Extend a LVM when the entire disk as a PV

1. Increase the VM’s hard disk size in vSphere Client
   • If there is a VM snapshot on the disk, its size cannot be changed. Remove all the snapshots first
   • After increasing the disk size, take a snapshot as the backup
2. Rescan the SCSI bus to verify the OS see the new space on the disk
   • ls /sys/class/scsi_host/
   • echo “- - -“ > /sys/class/scsci_host/<host_name>/scan
   • tail -f /var/log/message
   • or
   • ls /sys/class/scsi_disk/
   • each ‘1’ > /sys/class/scsi_disk/<0\:0\:0\:0>/device/rescan
   • tail -f /var/log/message
   • fdisk -l
3. Resize the PV
   • pvs
   • pvresize </dev/sdb>
   • 
4. Verify the VG automatically sees the new space
   • vgs
   • 
   • compare the vg_app VFree size in this screen with the one in step #3
5. Extend the LV
   • lvextend -l +100%FREE </dev/volume_group_name>/<logical_volume_name>
   • or lvextend -L+<size> /dev/<volume_group_name>/<logical_volume_name>
   • lvs
   • 
6. Resize the file system
• resize2fs /dev/<volume_group_name>/<logical_volume_name>
• df -h
• 
7. Remove the VM snapshot once confirming the data intact