[pca] Single-User revisited

[Rajiv Gunja]

First off, I do not recommend installing any patch in multi-user mode on a
Live System.

On our production/non-production(Test/Dev/Staging) servers we take extra
care to protect ourselves and make sure there is minimal down time. We use
Live Upgrade, so all patch installation occurs in normal business hours on
the ABE, thus avoiding any reboots that are required.

Here are the simple steps we follow:

   - On a spare disk or Root-Mirror, setup slices similar to Root-disk and
   run LU create. (This will create an exact image of the live system)
   - Mount the ABE (lumount abe-name)
   - Run PCA to download and install patches on the ABE (--root option)
   - In maintenance window - Activate the ABE (luactivate abe-name), and
   reboot.


If the OS look good, patching is done, we mirror the disks back, if not, we
activate the old OS and go back the old os. So down time for the clients is
only 25 minutes, instead of 4 to 6 hours installing patches in single use
mode.

-GGR

--
Rajiv G Gunja
Blog: http://ossrocks.blogspot.com


2008/9/11 John Horne <john.horne at plymouth.ac.uk>

> On Thu, 2008-09-11 at 09:44 -0400, Fred Chagnon wrote:
> > I know it's an age-old question. To patch in single-user, or not.
> >
> > I'm concerned mostly about the patches that require a reconfigure
> > reboot. For example sparc kernel patches 120011-14 or 127127-11. Has
> > anyone had any problems applying these patches in multi-user mode on a
> > running system?
> >
> I applied both patches to two systems yesterday. The patches were
> applied separately, and with a reconfigure reboot between them. The
> systems were running in multi-user mode, but are DNS servers and as such
> had no logged in 'users' as such. No problems with applying the patches.
>
> Obviously applying patches which should be done in single-user mode is
> risky. I always do just the one server completely first, rather than
> trying to patch two servers at once and having them both become
> unusable! Secondly, I always do a reconfigure reboot straight
> afterwards. The rebooting is not the problem for me, but accessing the
> server console is awkward, and so using single-user mode is awkward too.
>
> I do not use a proxy - although I will be looking in to it at a later
> date. My understanding though is that you should be able to get the
> patch from the proxy to the local machine using pca (with the -n option)
> when in multi-user mode. The patch is then on the local host. When it is
> in single-user mode you can then just run 'pca -i' and it sees that the
> patch file is already present, and so doesn't try and download it again
> from the proxy. That's my understanding, but I may well be very
> wrong! :-)
>
>
>
> John.
>
> --
> ---------------------------------------------------------------
> John Horne, University of Plymouth, UK  Tel: +44 (0)1752 587287
> E-mail: John.Horne at plymouth.ac.uk       Fax: +44 (0)1752 587001
>
>
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