On 3/8/07 4:54 AM, "Cory Snavely" <[EMAIL PROTECTED]> spake:
> 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. If only Tomcat were to go down on one of the hosts (say host A), this would allow the Apache on host A to still serve requests and talk to Tomcat on host B to fetch the content. Since > 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. I am also trying to avoid single points of failure. These hosts are both connected to a SAN, but want both hosts to have a copy of the data. I'm considering some form of on-demand synchronization, in addition to scheduled synchronization. For instance, when a new item is added having it trigger a synchronization to push the new data to the other node. Rsync is quite speedy. :-) > Make sure you run the indexer on only one instance. Good to know! > 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. What is the benefit to using the handle server with MySQL? What needs to be done to Dspace to get it to use the MySQL data rather than using the Dspace methods? Thanks for the input, Ryan > 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? -- 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
