Yeah, we're actually do Resin consulting and drive Scott Ferguson crazy with feature requests and bug reports. It might be nice to have the failover JVM support that Resin has, but that's more the domain of Avalon than James.
James should be a lot easier to cluster since SMTP is really geared to support failover. POP3 isn't quite so ready for it, but because these are both connection/stateful protocols instead of HTTP, clustering is significantly easier because you don't have to work extra hard to make sure the same user goes to the same box and otherwise track sessions. Once someone writes a patch to optionally storing locks in the db (or some place central), it should be as easy as sticking a network load balancer in front of a group of James servers. Serge Knystautas Loki Technologies - Unstoppable Websites http://www.lokitech.com/ ----- Original Message ----- From: "Keith Chew" <[EMAIL PROTECTED]> To: "James Users List" <[EMAIL PROTECTED]> Sent: Monday, January 21, 2002 3:15 PM Subject: RE: Clustering James? > > Just some clustering information: > > What would be nice to have is load balancing and fail-over, typically seen > in servers like Resin (www.caucho.com) and Jboss (www.jboss.org). What Resin > does is install a module in Apache, which makes it the *smart* balancer: > - knowing which resin servers are out there > - knowing how to forward requests to them > - knowing which ones are up/down > > I think we can achieve the same with James using LVS (linux virtual server > project). I have only tried this with Apache, and it works pertty well. > > So, when James supports SMTP clustering, we can have one LVS and several > James for a scalable and reliable system. > > Keep up the good work guys! > Keith > > -----Original Message----- > From: Serge Knystautas [mailto:[EMAIL PROTECTED]] > Sent: Tuesday, 22 January 2002 6:05 a.m. > To: James Users List > Subject: Re: Clustering James? > > > Actually, pop3 would work but SMTP would not. The problem is the spooling > system does not record in the DB when it is locking (processing) a message > in the spool. This means if server A receives a message via SMTP and dumps > it into the spool, both server A and server B would see the message and > potentially both grab it and store it in the outgoing spool, so messages > could get duplicated. pop3 actually works since once the message is in an > inbox, there's no chance of it getting duplicated. > > What someone would need to do is add a DB locking system, so as the spool > repository grabs a message, it records in the DB that it is grabbing that > message. The problem is a) how does each server uniquely identify itself to > the DB (so you know which server has the lock), and b) what happens if that > server dies, since the DB lock would remain. These aren't impossible to > address (perhaps just use IP address, or something like that, and probably > use some timeout to kill aged locks), but it's not ready yet. That said, > you're by no means the first to request this feature, and it would be a nice > differentiator for James since I don't know of other mail servers that > support this. > > Serge Knystautas > Loki Technologies - Unstoppable Websites > http://www.lokitech.com/ > ----- Original Message ----- > From: "Chris D" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Monday, January 21, 2002 4:46 PM > Subject: Clustering James? > > > > Hello, > > > > I would like to use James strictly as a mail-forwarding server (SMTP). I > > have been able to install James and configure the JDBCAlias mailet to > > perform forwarding based on a database table. I also intend on moving the > > user repository into the database as well. > > > > My question is this. Can I have two servers in a cluster running > instances > > of James to forward mail? I am assuming that since I am only using SMTP > > there should not be a problem. Also, since only one server will be > > accepting a given request, there should not be a problem with duplicated > > messages. > > > > Any thoughts? -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
