Dynamic Root Disk: Quick Start & Best Practices

Creating a Clone

Overview

All uses of DRD begin with creating a clone of the root volume group. After discussing clone creation,

we will present best practices a system administrator can follow to make software maintenance tasks

easier.

The drd clone command creates a bootable disk containing a copy of the LVM volume group or

VxVM disk group containing the root file system “/". In this white paper, “root group” refers to the

LVM volume group or VxVM disk group that contains the root (“/”) file system. The term “logical

volume” refers to an LVM logical volume or a VxVM volume.

Important Considerations

• For VxVM-based systems, all the volumes in the root disk group must reside on a single disk.

• For LVM based-systems, the root disk group may be spread across multiple disks.

• For VxVM-based systems, the root disk group may be mirrored to additional disks. If the root disk

group is mirrored, all

volumes in the root disk group must contain the same number of mirrors. For

example, a configuration where all volumes except swapvol are mirrored is not supported.

• The source of the drd clone command—the volume group that is copied—is the LVM volume

group or VxVM disk group containing the root (“/”) file system.

• The drd clone operation clones the root group. It is not appropriate for systems where the HP-

UX operating system resides in multiple volume groups. (For example, if / resides in vg00, but

/var resides in vg01, then the system is not appropriate for DRD.)

• The target of the drd clone operation must be a single disk. However, you can use the

-x mirror_disk option to mirror the clone to another disk.

Choosing a Target Disk

The target disk must be specified as a block device file.

• An appropriate target disk should be writeable by the system, not currently in use by other

applications, and large enough to hold a copy of each logical volume in the root group being

cloned.

• The disk needs to be as big as the allocated space, not the used space, for each logical volume.

For example, if the logical volume containing /var has been allocated 5 GB, but is only 70% full,

you will still need 5 GB for the /var logical volume in the cloned group.

Important:

It is the system administrator's responsibility to determine which disks are not currently in use and may

therefore be used for a clone.

Please see the Dynamic Root Disk Administrator’s Guide, Chapter 2, which can be found at:

http://bizsupport1.austin.hp.com/bc/docs/support/SupportManual/c01918754/c01918754.pdf, for more

details on tools and utilities that can be used to determine an appropriate target disk.