Upgrade from Version 6.3

[Chris Clawson]

I have a test server on my home network, which is a partial clone of my live webserver installation of 6.3. I am considering upgrading the test machine to 7 Beta 4.

The goal is to temporarily preserve the working 6.3 install, while upgrading the packages, like Java JDK, Ant, Maven, PostgreSQL, etc. This would be practice for an eventual upgrade of my live server.

Can a DSpace 6.3 install survive such a package upgrade?

Is it practical to attempt a DSpace Beta 4 upgrade on an existing database? (This is a test system - no real harm will occur if it breaks).

I am no I.T. pro, but I did build this home server, myself. You comment and guidance is welcome - thanks.

[Mark H. Wood]

On Wed, Oct 14, 2020 at 05:02:49PM -0700, Chris Clawson wrote:
> I have a test server on my home network, which is a partial clone of my
> live webserver installation of 6.3. I am considering upgrading the test
> machine to 7 Beta 4.
> The goal is to temporarily preserve the working 6.3 install, while
> upgrading the packages, like Java JDK, Ant, Maven, PostgreSQL, etc. This
> would be practice for an eventual upgrade of my live server.
> Can a DSpace 6.3 install survive such a package upgrade?
> Is it practical to attempt a DSpace Beta 4 upgrade on an existing database?

Of course it's important to remember that it's a Beta release, which
means that it may break things in ways we don't yet know of.

One thing I can point out is that DSpace 7 requires upgrading Solr
from v4 to v7. There were incompatible changes in the field analyzers
somewhere between 4 and 7, so you'll have to re-create all of the Solr
cores that you use, with the updated schemas that are provided. The
DSpace 7 upgrade instructions tell you how to do this. The resulting
cores are not backward-compatible with Solr 4, so in this sense your
DSpace 6 instance will not survive the upgrade. But the upgraded
DSpace 7 instance should still work, so in that sense it does survive.
(Maybe we should be using a more precise word.)

OTOH since version 5 Solr expects to run in its own container, so
you'll be installing it separately. Supposing that you have enough
storage, you could just leave the v4 cores where they are (within the
DSpace directory tree) and create the v7 cores somewhere else. If you
don't have enough storage for both, it's always a good idea to have a
supply of high-capacity USB memory sticks when doing something like
this. It's easy to shut down Solr and copy cores to a safe place.

There are a number of database updates which will be applied
automatically when DSpace 7 is started. There is no built-in support
for reversing them, and some may be irreversible. Dumping the
database before you begin the upgrade would be a Realy Good Idea.

There are no changes to the form or content of the assetstore(s).

DSpace 7 requires JDK 11, and DSpace 6 may not run on 11, so if you
want to switch back and forth you may need both.

Anyway, it is intended that DSpace be upgradable from v6 to v7. A lot
of work goes into each major version to provide a continuing upgrade
path.

--
Mark H. Wood
Lead Technology Analyst

University Library
Indiana University - Purdue University Indianapolis
755 W. Michigan Street
Indianapolis, IN 46202
317-274-0749
www.ulib.iupui.edu

[Jose Blanco]

Mark, I have a related question.  We want to bring up a clean instance of dspace 7 on the same server that we use for production that runs 6.3.  It sounds from your response about that our issue would be:

DSpace 7 requires JDK 11, and DSpace 6 may not run on 11, so if you
want to switch back and forth you may need both.

So therefore it would not be possible to have a separate dspace 7 on the production server that is running 6.3. I think the other things you mentioned would not be a problem, since the dspace 7 would be a new clean installation, and not an upgrade to 6.3.  Does that make sense?

Thank you!

-Jose

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[Mark H. Wood]

On Thu, Oct 15, 2020 at 12:25:35PM -0400, Jose Blanco wrote:
> Mark, I have a related question. We want to bring up a clean instance of
> dspace 7 on the same server that we use for production that runs 6.3. It
> sounds from your response about that our issue would be:
>
>

> *DSpace 7 requires JDK 11, and DSpace 6 may not run on 11, so if youwant to
> switch back and forth you may need both.*

>
> So therefore it would not be possible to have a separate dspace 7 on the
> production server that is running 6.3. I think the other things you
> mentioned would not be a problem, since the dspace 7 would be a new clean
> installation, and not an upgrade to 6.3. Does that make sense?

It is possible to run them side-by-side in two different Tomcat
instances under different JVMs. For example, on Gentoo Linux I've
installed both the OpenJDK 8 and 11 "slots", as well as Tomcat 7 and
8.5 slots. The Tomcat startup script can be configured as to which
JVM to use, so I can have a Tomcat 7 running on JDK 8 and a Tomcat 8.5
(on different ports, of course!) running on JDK 11. The Gentoo Tomcat
packages also include a tool to set up multiple instances of the same
slot, and I could have done it that way.

Your OS may provide similar facilities. Or you can rig up multiple
Tomcat instances yourself.

[Chris Clawson]

Hmmm.. It sounds like an upgrade is a one time deal, with no going back. That makes me glad I have a test server. The 'side by side' install sounds interesting, but this conversation doesn't provide any detail or links explaining how to do that. If that were practical, I was thinking DSpace 7 might be installed alongside the live 6.3, and once everything was migrated properly on a Release version of 7, the 6.3 install might be retired. Is that a viable idea?

[Mark H. Wood]

On Thu, Oct 15, 2020 at 11:04:42AM -0700, Chris Clawson wrote:
> Hmmm.. It sounds like an upgrade is a one time deal, with no going back.

Well, it's easy enough to roll back in a testing situation: just
restore the database dump and copy back your saved Solr cores. You
could switch back and forth as needed, as long as you can accept
losing new submissions to the current version when you switch
versions.

> That makes me glad I have a test server. The 'side by side' install sounds
> interesting, but this conversation doesn't provide any detail or links
> explaining how to do that. If that were practical, I was thinking DSpace 7
> might be installed alongside the live 6.3, and once everything was migrated
> properly on a Release version of 7, the 6.3 install might be retired. Is
> that a viable idea?

If you mean, parallel *production* versions: how would you handle new
submissions, which would only be installed in one or the other?