> -----Original Message----- > From: Christopher Schultz [mailto:ch...@christopherschultz.net] > Sent: Wednesday, August 24, 2011 9:08 AM > To: Tomcat Users List > Subject: Re: jvmRoute generation > > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Jeffrey, > > On 8/24/2011 9:59 AM, Jeffrey Janner wrote: > > As Chris pointed out, it is mostly used by folks running with > > "sticky-sessions" > > Actually, use of the jvmRoute with non-sticky sessions seems like an > unnecessary step to me, since non-sticky sessions implies that you > either have no sessions (and it doesn't matter at all) or you have > replicated sessions where it doesn't matter which cluster member you > reach. > > > but from what I've been able to tell, most folks set up their > > clusters that way. It lessens the headaches. > > Practically speaking, clustering Tomcat instances means session > replication, which (if you ask me) does not warrant session stickiness > (though session replication does take some time... I don't know enough > about TC's clustering to know whether race conditions are possible or > probable). >
Yea, it's that back-end replication stuff that causes all the headaches. From what I've seen, mostly on this list, folks tend to set up the cluster w/replication, but keep the sessions sticky, as a fail-over scenario. That is, they want to avoid requiring login on a fail-over. The httpd-JK does a pretty good job of load-balancing the sessions between the clusters. Session replication delay issues totally depend on what method you are using to do the replication. Only race conditions I can think of would be caused by subsequent requests coming in faster than replication can occur. In some methods you might be able to avoid that, others, not so easy. > For my money, I'd go for sticky sessions and no replication at all. If > you really need cluster-wide session access, look to other solutions > (memcached, db-backed sessions, etc.). > > - -chris __________________________________________________________________________ Confidentiality Notice: This Transmission (including any attachments) may contain information that is privileged, confidential, and exempt from disclosure under applicable law. If the reader of this message is not the intended recipient you are hereby notified that any dissemination, distribution, or copying of this communication is strictly prohibited. If you have received this transmission in error, please immediately reply to the sender or telephone (512) 343-9100 and delete this transmission from your system.
