The Virtualization Cookbook for SLES 10 SP2 - z/VM - IBM

13.2 Adding a logical volume
There are times when you require more disk space than a single direct access storage device
(DASD) volume provides. For example, if you want to have a shared /home/ directory you will
want it to be of sufficient size. When this is the case, you can use the Logical Volume
Manager (LVM) to combine multiple DASD volumes into one logical volume.
The following process describes how to create a logical volume with additional DASD on a
Linux guest. The overall steps in adding a logical volume are:
► “Adding DASD” on page 191
► “Creating a logical volume and file system” on page 194
► “Updating the file system table” on page 197
13.2.1 Creating a logical volume and file system
The overall steps involved in creating a logical volume are:
► Create physical volumes from the two partitions
► Create a single volume group
► Create a single logical volume
► Make a file system from the logical volume
Figure 13-1 on page 194 shows a block diagram of the logical volume manager reflecting this
example.
Physical Volume - /dev/dasde1
Physical Extent (PE)
Physical Extent (PE)
Physical Extent (PE)
Physical Extent (PE)
Figure 13-1 LVM block diagram
Creating physical volumes from the two DASD
To create physical volumes, perform the following steps:
194 The Virtualization Cookbook for RHEL 6
Volume Group - homevg
Physical Volume - /dev/dasdf1
Physical Extent (PE)
Physical Extent (PE)
Physical Extent (PE)
Physical Extent (PE)
Logical Volume - homelv (/dev/homevg/homelv)
ext3 file system
mounted over /home/