Dynamic Root Disk Frequently Asked Questions (766143-001, March 2014)

the booted system. For example, if the two disks are on the same SCSI chain, then I/O
to the clone will affect performance of I/O on the booted system. DRD's performance is
similar to system performance when using Ignite to create recovery images, which
many system administrators find acceptable.
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1-21. Q:
IgniteUX offers net and tape images. What is the advantage of DRD?
A:
DRD provides a “make-disk-recovery” solution and has several advantages over
IgniteUX net and tape images:
 No tape drive is needed
 No impact on network performance will occur
 No security issues of transferring data across the network will occur
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1-22. Q:
How can I be sure the patches I install are safe in a DRD environment?
A:
You can install patches packaged in standard Software Distributor (SD) format. Most
patches for HP–UX 11.23 September, 2004 and above are DRD safe. However, the
DRD product maintains a list of those patches known to be unsafe. When the revision
of SD required by DRD is run by drd runcmd, it makes sure that a patch does not
appear in the list before installing or removing it.
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
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1-24.Q:
Does DRD Support SoftReboot feature?
A:
Yes. It can be used with the following command only.
drd activate -x softreboot=true
If SoftReboot is not installed on the system, this option is invalid. SoftReboot feature is
supported from HP-UX B.11.31.1109 fusion release onwards i.e. HP-UX 11iv3 operating system
environment.
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?