Dynamic Root Disk Frequently Asked Questions (August 2010)

For more information about DRD-unsafe patches, see the Dynamic Root Disk: Quick Start and Best Practices white paper at
http://www.hp.com/go/drd-docs
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1-23. Q:What are the DRD considerations for legacy Device Special Files (DSFs)?
A: Due to system calls DRD depends on, DRD expects legacy Device Special Files (DSFs) to be present and the legacy naming model to
be enabled on HP-UX 11i v3 (11.31) servers. HP recommends only partial migration to persistent DSFs be performed. For details of
migration to persistent DSFs, see the http://www.hp.com/go/hpux-core-docs
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2- Using Dynamic Root Disk Commands
2-1. How do I use DRD commands?
2-2. Will I need to reboot while installing DRD?
2-3. How can I tell if I have chosen a sufficiently large target disk for a DRD clone?
2-4. If I am running multiple drd runcmd operations, can I avoid mounting and unmounting the inactive system image for each runcmd
execution?
2-5. Does the DRD clone operation verify that the target is not in use or part of another VG? Once the root disk is cloned, is there anything in the
operating system that prevents the non-active target from being reused? How can inactive targets be identified?
2-6. Can I vgimport the target disk as /dev/vgtmp?
2-7. Can DRD show whether DRD is configured or not configured?
2-8. Some processes in DRD, particularly drd clone and drd runcmd, take a significant amount of time. Can these processes be interrupted?
2-1. Q: How do I use DRD commands?
A: In some cases, you simply enter the command. For example, if you enter drd mount, the command mounts the inactive system image
file set. In other cases, you need to use one or more command options. For example, drd clone always needs the -t option with the
target disk identity.
You can also enter the drd runcmd followed by an SD command. For example,
drd runcmd swlist.
drd runcmd limits the action of swlist to just the inactive system image.
For more information about these commands, see the Dynamic Root Disk Administration Guide for HP-UX 11i (B11.23) on the
Information Library page.
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2-2. Q: Will I need to reboot while installing DRD?
A: On HP-UX 11i v3 (11.31) systems, there are no required patches for DRD so installing DRD will not cause a reboot.
Neither DRD nor its corequisites require a reboot. However, one of DRD's corequisites, patch PHCO_34195, does have a further
corequisite on two other patches, PHKL_33024 and PHKL_33025, that do require a reboot. Most systems will already have these two
patches installed and will have no need for a reboot.
To determine definitely whether your installation of DRD will require a reboot, preview the installation and check whether any kernel
patches (PHKL_*) are included in the selection at the end of the analysis phase of the install.
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2-3. Q: How can I tell if I have chosen a sufficiently large target disk for a DRD clone?
A: A simple mechanism for determining if you have chosen a sufficiently large disk is to run a preview of the drd clone command:
drd clone -p -v -t path_to_block_DSF
Where path_to_block_DSF is of the form:
HP-UX 11i v2: /dev/disk/cXtXdX
HP-UX 11i v3: /dev/disk/diskX
The preview operation includes the disk space analysis needed to see if the target disk is sufficiently large.