I'm not clear on why you would want load-balancing both in *front* of
Apache *and between* Apache and Tomcat. In particular I would think if
you had the former you would not benefit from the latter. I guess you're
concerned about Tomcat failing independently of Apache. In my case, I've
just eliminated Apache from the picture.

At any rate, re: the assetstore, if you want a load-balanced
environment, I am quite sure that real-time synchronization is
necessary. Even with an hourly rsync--problematic at best with a large
repository, BTW--a deposit on one instance and a subsequent attempted
retrieval of it on the other would cause issues. There are a number of
ways to share a file system among several servers but I would think that
the most accessible would be any reasonable NAS storage backend
depending on your existing storage infrastructure.

Make sure you run the indexer on only one instance.

I run two regular handle servers redundantly, not against DSpace, but
against MySQL with bidirectional MySQL replication. The folks at CNRI
helped me work through the issues involved, which mainly involved having
a shared private key between the two and making sure that the two
servers were configured as masters so they did not try to use handle
replication. I would think that redundant handle servers operating
against DSpace (that is, DSpace methods for Postgres or MySQL access)
would be about the same thing--just making sure that the handle server
configurations are identical on each server.

Cory Snavely
University of Michigan Library IT Core Services

On Wed, 2007-03-07 at 11:52 -0800, Ryan Ordway wrote:
> I have been digging around to find information about sites using load
> balancing and/or clustering with their Dspace installations. All I could
> find was mention of load balancing web requests to multiple Tomcat instances
> using mod_jk.
> 
> First some background, and then my question:
> 
> What I am looking to do is put my Dspace web servers behind my load balancer
> to balance the HTTP requests. The web servers then both load balance their
> Tomcat connections via mod_jk to each other, with their own instances being
> weighted heavier so that they will prefer localhost.
> 
> For the database, for now I'm just using a single Postgres instance. I'm
> hoping to get Dspace ported to MySQL to take advantage of my existing MySQL
> cluster. 
> 
> My question is, are there any issues to watch for? Will just rsync'ing the
> assetstore between the two web/app servers suffice? Are there any issues
> with running multiple handle servers?
> 
> Thanks,
> 
> Ryan
> 
> --
> Ryan Ordway                          E-mail:   [EMAIL PROTECTED]
> Unix Systems Administrator             [EMAIL PROTECTED]
> OSU Libraries, Corvallis, OR 97370        Office: Valley Library #4657
> 
> 
> 
> -------------------------------------------------------------------------
> Take Surveys. Earn Cash. Influence the Future of IT
> Join SourceForge.net's Techsay panel and you'll get the chance to share your
> opinions on IT & business topics through brief surveys-and earn cash
> http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
> _______________________________________________
> DSpace-tech mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/dspace-tech


-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
_______________________________________________
DSpace-tech mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/dspace-tech

Reply via email to