From: John Gormley (jgormley@scu.edu.au)
Date: Mon Feb 10 2003 - 17:43:43 EST
Thankyou all for the quick replies from:
Robert Mulley
Ronny Eliahu
Nicola Miutinovic
Kjell Andresen
Udo Grabowski
Johan Brusche
Thomas Blinn
Ram Rao
Bryan Lavelle
Joe Carrico
Chris Adams
The answers were mostly adamant that this could not/should not be done in a
standalone system, the exceptions were to a V5 cluster system or via NFS.
Chris Adams has made it work as a temporary measure, but warns of the risks
involved. Seems the version 5 man pages, although slightly different, have
the same message as the version 4.0g man pages, my apologies for not
including the version I was looking at.
Answers in full follow the original question.
Original Question:
Can anyone out there tell me definitavely whether addvol can or can not be
used on the root domain? I have a 1996 course text which says it cannot be
used, the man pages say "AdvFS does not support a multivolume root file
system. You cannot use the addvol utility to expand root_domain". This would
normally be enough to go on, but, HP says it can or cannot be done depending
on who you talk to and the Tru64 archives seem to have a lot of examples of
people who have used it. So, is it that it is possible but not supported?
Relpies in Full:
Robert Mulley
I would advise against doing such an action. In fact man addvol brings up
the message:
AdvFS does not support a multivolume root file system. You cannot use the
addvol utility to expand root_domain. This does not apply to cluster root
domains.
I would trust the man page. You may however be able to expand the
root_domain by addvoling a disk then removing the old disk. Not sure about
that though. BTW Having 2 volumes in the root_domain doubles your chances of
a hard disk failure bringing down the machine.
************************************************************************
Ronny Eliahu
No, NOT on root_domain
************************************************************************
Nicola Milutinovic
root_domain can have ONLY ONE VOLUME. Look at man pages for "mkfdmn" and
you'll
see that there is special switch "-r" for creating root domains, which
prevents
it from having more than one volume and one file-set.
***********************************************************************
Kjell Andresen
My v5.1B "man addvol" states:
RESTRICTIONS
You must be the root user to use this utility.
AdvFS does not support a multivolume root file system. You cannot use the
addvol utility to expand root_domain. This does not apply to cluster root
domains.
***********************************************************************
Udo Grabowski
As far as aI know, it's only possible for a Cluster File System
(officially).
***********************************************************************
Johan Brusche
One can definitely NOT expand the root partition with addvol.
the root_domain is created during istallation with the -r switch.
At on time there was a error in the Factory installed software
procedure that created the root_domain without the -r switch.
This made it possible to addvol onto root_domain, but such root_domain
is unaccessible when booted from CD since the AdvFS license is not
active in that environment.
In a V5 cluster the cluster_root can be expanded with addvol , but NOT
the root bootpartition.
***********************************************************************
Thomas Blinn
You can't do it with a root domain from which you boot -- there is no
support in the console firmware or the secondary bootstrap program for
dealing with a multivolume boot disk.
In a TruCluster system (V5.x) the member systems each have a boot disk
that has an AdvFS root file system that is used SOLELY for booting and
to hold some member-specific configuration files that are used to find
the cluster-wide root file system and mount it (in a standalone system
the boot disk MUST contain the root file system). As it happens, the
code that mounts the cluster-wide root file system can deal with having
it be a multi-volume file system; in fact, once the first member boots
and forms the cluster, it "serves" the file system to the other members
who don't actually do direct I/O to the volumes.
In a network booted system, the root file system is served via NFS and
it could be on a multi-volume AdvFS domain on the NFS server, but that
isn't visible to the booted kernel which mounts an NFS served root.
So there are cases where you can do it, but NOT in the standalone system
case where you are booting off the disk that contains the root, nor in
the TruCluster case where the member boot disk's member-specific root
has to be single volume domain.
*********************************************************************
Ram Rao
Addvol on root_domain will not work! I would like to know the source of
misinformation claming that it does work.
The only exception is that in a V5 cluster, it will work because the
cluster root domain is different from the member boot disk.
*********************************************************************
Bryan Lavelle
It can *not* be used on the root volume, with the only exception being
cluster_root in V5 clustering, which obviously is a different animal.
*********************************************************************
Joe Carrico
You can't add a volume to root_domain, however if you are running TruCluser
Server you can add a volume to the cluster_root domain. You may have to do
this when performing a rolling upgrade (installupdate or dupatch).
*********************************************************************
Chris Adams
It is possible - I've done it temporarily (while moving from one drive
to another). However, there are risks involved: if anything happens
like a crash or required shutdown while there are mulitple volumes, the
system will not boot, as AFAIK the boot loader doesn't understand
multivolume roots.
Regards, John
John Gormley
Senior Unix Systems Administrator
Information Technology and Telecommunications Services
Southern Cross University
LISMORE NSW
AUSTRALIA
(02) 6620 3365
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