Managing Systems and Workgroups: A Guide for HP-UX System Administrators

Administering a System: Managing Disks and Files

Managing Disks

Chapter 6 577

Extending a Logical Volume to a Speciﬁc Disk

Suppose you want to create a 300 MB logical volume and put 100 MB on

your ﬁrst disk, another 100 MB on your second disk, and 100 MB on your

third disk. To do so, follow these steps:

Step 1. After making the disks physical volumes and creating your volume

group, create a logical volume named lvol1 of size 0.

lvcreate -n lvol1 /dev/vg01

Step 2. Now allocate a total of 25 extents to the logical volume on the ﬁrst

physical volume. (We are assuming in this example that each physical

extent is 4MB, the default value.)

lvextend -l 25 /dev/vg01/lvol1 /dev/dsk/c1t0d0

Step 3. Then increase the total number of physical extents allocated to the

logical volume for the remaining physical volumes by 25. In each case,

the additional 25 extents are allocated to the disk speciﬁed.

lvextend -l 50 /dev/vg01/lvol1 /dev/dsk/c2t0d0

lvextend -l 75 /dev/vg01/lvol1 /dev/dsk/c3t0d0

Note that when you use the -l option (lowercase L) of lvextend, you

specify space in logical extents.

Now suppose you have two disks in a volume group, both identical

models. You currently have a 275 MB logical volume that resides on only

one of the disks. You want to extend the logical volume size to 400 MB,

making sure the 125 MB increase is allocated to the other disk.

Again you extend the logical volume to a speciﬁc disk.

lvextend -L 400 /dev/vg01/lvol2 /dev/dsk/c2t0d0

Here, when you use the -L option (uppercase), you are specifying space

in megabytes, not logical extents.

See lvextend (1M) for complete information on command options.