SUMMARY - Upgrade vs. Install

From: Becker, Mark (
Date: Wed Sep 11 1996 - 17:13:00 CDT

Thanks to all who have responded, and responded so rapidly. Greatly

Apologies if I missed anyone.

The answer is:

As best as I can determine, upgrading _may_ work, and when it does work it
works well,
but also may fail and if it does
 one will loose a fair amount of time.
The reasons for failure were not all identified, although a key one was lack
of space in the root
and /var partitions.

Going to I found infodoc 11374 - "Debugging problems when
upgrading to Solaris"

It tells how to use pfupgrade in dry run mode to identify problems before
starting the upgrade.
This program can be run from the CDROM mini root - it is not installed on my
2.4 system.

In any case it seems cleaner and probably quicker to do an install rather
than the upgrade.

I've copied the key parts of received messages below for the reader to

BTW, the reason we are going to 2.4 rather than 2.5 is because we've been
running the new application
(the one that is forcing the upgrade)
in test mode under 2.4 for 8 months now, and have yet to run under 2.5.
Given the importance of this application, extreme caution is required.

Thanks again,

Mark Becker

From: thielen

upgrade to 2.5

It's really easy... Unless you want to change the size of partitions
or swap, I'd upgrade..


Susan KJ Thielen System/Network Manager
Imaging Lab, Robarts Research Institute Phone: (519) 663-5777x4029
PO Box 5015, 100 Perth Drive Fax: (519) 663-3900
London, ON N6A 5K8 Canada E-mail:

From: Benjamin Cline
I've done maybe 15-20 Solaris upgrades, the majority of which from 2.3 ->
2.4 and a few from 2.4 -> 2.5, and never had a problem. I definitely
think upgrading is the way to go, especially on an important production
system, where I expect you need to minimize down time.


Benjamin R. Cline Harrison & Troxell, Inc.
                     Quis Custodiet Ipsos Custodes?

From: tkevans

Seriously, the upgrade, if it works at all (i.e., you do have enough
diskspace) will take you most of a day to do. This is far more time
than it'll take to back up the system, and do an initial install,
with preservation of your purely local data filesystems. You can
do your initial install, plus restoring local configuration data, much
more quickly.

Just my 2 cents

Tim Evans | E.I. du Pont de Nemours & Co. | Experimental Station
(302) 695-9353/8638 (FAX) | P.O. Box 80357
EVANSTK AT A1 AT ESVAX | Wilmington, Delaware 19880-0357

From: amy.hollander

Don't upgrade from 2.3 or lower.

Upgrade from 2.4 and up.
You should do a complete install of 2.4 or 2.5 or 2.5.1 if you are
running 2.3 or lower.

From: Rahul Roy

You would be better off reinstalling Solaris 2.4 - infact you should get
hold of Solaris 2.5/2.5.1 which are a shade(s) better than their earlier


Rahul Roy Voice: (609) 727-4600 Ext.2650
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From: jworache

We have only had a couple OS upgrade successes.

>From 2.3 to 2.4 on one machine - all others failed
>From 2.5 to 2.5.1

Good Luck.

From: Daniel J Blander - Sr. Systems Engineer for ACS

2.2 to 2.4? Do an install. The upgrade will be a mess and the differences
are drastic enough to not trust the upgrade process....

On the 6xx series and servers we have a basic rule of thumb....

        32mb /
        64mb minimum /var
        250mb minimum /usr

All else is up to you (/opt /epxort)

 Daniel Blander =8^)
 Sr. Systems Engineer Applied Computer Solutions
 Phone: (714) 842.7800 Fax: (714) 842.8299
 The Official Applied Computer Solutions Home Page
             and Tech Tip of the Week:

From: Trevor Paquette

Do an install. I've never had any luck with an upgrade. With a new install
you know exactly what is on your system.

As for partition sizes.. why worry anymore? Do what I do. Create a 1 GB
(slice 0) call it /, and install ALL to there. /usr, /var and / all mounted
on one filesystem. You'll never have to worry about running out of space
you did before. We have 42 systems here configured like that and it has
saved us ALOT of headaches compared to what we used to have to deal with.
 Name:Trevor Paquette |Network ServiCenters |Work:(403) 543-2355|600, 777 8th Ave SW | Fax:(403) 290-8400 |Calgary, Ab, Canada
      |ICBM:51'05"N/114'01"W |T2P 3R5 |Mind:In the

From: Rachel Polanskis


> I've got a few questions:
> 1. How much free space do I need in /, /var, and other partitions?
> 2. How successful have upgrades been for you who've tried them?
Although the small machine I updated to Solaris-2.5.1 was not a production
machine I found it was almost simpler than installing something like
macOS or windows! If that means anything.
provided you have your operating system on it's own disk or partition,
you could upgrade to Solaris 2.5.1 simply.

What I did was backup information about certain files in /etc
like the hosts file for example, I also ensured that anything that I had
installed on my OS partitions was moved - such as /var/mail, and the
information contained in crontabs was safely stored away.

Once I was satisfied that I had saved all non Solaris files that I wanted
to keep, I selected the install routine that completely reinitialised
the hard disk.

At this point the only thing I had left on the OS disk was a partition
of user directories (which I had backed up) Solaris let me secure any
partitions I did not want to overwrite, and then let me adjust the remaining
space to suit my new install.

By the time i had finished, I had a completely new 2.5.1 installed and
had repartitioned the remains of my disk to a much better format than i
had had previously.

All the files on my other disks I left untouched since I had unmounted
them and removed them from the SCSI train before the install.

All I had to do then was boot -r to make 2.5.1 see my disks again,
and then edit /etc/vfstab to add them in where I wanted them.

In the end, I only lost 2 PD binaries that I forgot to copy into my
backup set, and now have a fully restored machine, with the replacement
of a few symlinks.

of course I had to edit the passwd file and the group file to add my
users back, but there was no loss of important data.

I think you would be better doing a full install as opposed to an
upgrade, as you get some legacy files hangng around, and it is not a
"clean" process.

Also, if like me you were unhappy with the partition layout of your
previous setup, here's your chance!

I think provided you only have the OS on the main disk,you should not
have to backup too much - if you keep your data && 3rd party stuff on it's
own partition.

Compare that to windows, where everything goes into the one directory-
and a reinstall of windows rquires *everything* to be discarded and
reloaded :)


Rachel Polanskis Kingswood, Greater Western Sydney,
                Witty comment revoked due to funding cuts

From: boenning


the step from 2.2 to 2.4 was a really big one. The upgrade option could
bring you in any kind of trouble, withou saving much time. You'll
find the better way with a new installation.


BTW, why do you want to step up to Solaris 2.4 and not to 2.5 ?

From: David Lee

Why just to 2.4? The current OS is 2.5.1 .

> I've searched Usenet and Manager summaries for the pro's and con's of
> upgrading vs installing
> and after weighing these I am leaning toward doing an upgrade after making

> two complete backups
> on brand new 8mm tapes.

We keep our systems as clean (i.e. close to the distribution) as possible,
so the number of local changes is small. So we never bother with "upgrade",
we simply install the new OS, then re-apply our local changes.

I understand (but from from scanning sun-managers rather than personal
experience) that:
1. upgrade can take longer than install
2. more importantly, upgrade can fail, especially when starting from
    Solaris 2.2 or 2.3, leaving you stuck between the two, so you end up
    installing anyway.

(I may, of course, be wrong: hopefully you will receive other replies
based on personal experience which will be far more use than mine.)

How much space is available to you? How much do you want?
This will be site-specific.

For us, the automatic partition-sizing seems to be very tight, and
I always increase what it gives to "/" and "/var". We use process
accounting and various other things which can require several 10s of Mb
in "/var". It is also worth increasing "/usr" slightly above auto-size
because patch installation can make this bigger. Patch installation
of course also makes significant demands on "/var", especially if
you use the default option to backout which also stores the original
versions in the depths of "/var".

> 2. How successful have upgrades been for you who've tried them?

Never tried: only seen the warnings.

> Any new thoughts pro/con on the wisdom of upgrading vs installing will
> be appreciated.

Hope it goes well, whichever you choose.

: David Lee I.T. Service :
: Systems Programmer Computer Centre :
: University of Durham :
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