Dot Hill Systems SANnet II 200 Service Manual download pdf (Page 199)

Appendix I Configuring an HP Server Running the HP-UX Operating System I-5

As with many system administration tasks, you can use SAM to create and maintain

logical volumes. However, some functions can only be performed with HP-UX

commands. The procedures in this appendix are performed using the command-line

interface rather than SAM.

I.5 Definitions of Common Terms

Volume groups are HP-UX’s method for dividing and allocating disk storage capacity.

Volume groups can be used to subdivide a large partition of storage into smaller units

of usable space called logical volumes.

Each volume group is divided into logical volumes, which are seen by the applications

as individual disks. They can be accessed as either character or block devices and can

contain their own file systems.

The underlying physical storage in a volume group consists of one or more physical

volumes. A physical volume can be a single physical disk or a partition of a disk array.

Each physical volume is divided into units called physical extents. The default size of

these units is 4 Mbyte, but can range in size from 1 Mbyte to 256 Mbyte. The

maximum number of physical extents that a volume group can contain is 65,535. With

the default size of 4 Mbyte, this limits the size of the volume group to 255 Gbyte.

To create a volume group larger than 255 Gbyte, you must increase the size of the

physical extents when creating the volume group. Refer to vgcreate(1m) for further

information.

I.6 Creating a Physical Volume

To use a storage resource in the LVM, it must first be initialized into a physical volume

(also called an LVM disk).

1. Log in as

root, or become superuser if you are not logged in with root user

privileges.

2. Select one or more partitions on the array that you want to use. The output of

ioscan(1M) shows the disks attached to the system and their device names:

# ioscan -fnC disk

Class I H/W Path Driver S/W State H/W Type Description

disk 1 0/12/0/0.6.0 sdisk CLAIMED DEVICE SANnet II 200F R

/dev/dsk/c12t6d2 /dev/rdsk/c12t6d2

1 2 ... 194 195 196 197 198 199 200 201 202 203 204 ... 209 210

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Dot Hill Systems SANnet II 200 Service Manual Page 199