HP Dynamic Root Disk (DRD) Choosing a target disk, Using DRD for limited disk availability checks

2.3 Choosing a target disk

CAUTION: It is the system administrator's responsibility to identify a target disk that is not currently in use! Cloning a disk removes all current data on the target disk.

In Example 2-1, the disk with the active system image is /dev/dsk/c2t3d0. You need to choose a free disk to be the target of the drd clone command. Your system may have many more disks than Example 2-1shows.

The target disk must:

•Be a block device special file.

•Be writeable by the system.

•Not currently be in use by other applications.

•Be large enough to hold a copy of each logical volume in the root group.

The target's physical disk need not be as large as the disk allocated for the root group, as long as there is enough space for a copy of each logical volume in the root group. However, the disk needs to be larger than the used space in each logical volume because each logical volume will be created with the number of physical extents currently allocated to the corresponding root group logical volume.

Example 2-1shows three system disks: /dev/dsk/c0t0d0, /dev/dsk/c1t2d0, and /dev/ dsk/c2t3d0. You need to determine which disks are available and large enough.

2.4 Using other utilities to determine disk availability

You can determine which disks are in use with the lvm(7M) (Logical Volume Manager) and VxVM (Veritas Volume Manager) commands. For example, to see which disks are in use by lvm, enter this command:

# /usr/sbin/vgdisplay -v /usr/bin/more

and look in the output for PV Name, which describes physical volumes.

This information is under the Physical Volumes heading. It looks similar to this:

--- Physical Volumes ---

PV	Name	/dev/dsk/c2t3d0
PV	Status	available
Total PE		4340
Free PE		428
Autoswitch		On

You can use the vxdisk -o alldgs list command to display information about all disks managed by VxVM. Do not specify any disk in use by VxVM as a clone target.

The swapinfo command can be used to display information about disks currently used for swap.

The HP System Management Homepage, hpsmh(1M), or System Administration Manager, sam(1M), can be used to investigate the disks on the system and their current usage.

2.5 Using DRD for limited disk availability checks

You can use drd clone with the -poption to get minimal availability information about a disk. (See the following section for an example.)

The drd clone command performs the following checks:

12 Cloning the active system image