-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Howard,
On 2/5/13 8:29 PM, Howard W. Smith, Jr. wrote: > Chris, On Sun, Feb 3, 2013 at 12:39 PM, Christopher Schultz > <ch...@christopherschultz.net> wrote: > >> If your requirements allow for users to have to re-authenticate >> when you have a failover-event, then I highly recommend that you >> use sticky-sessions /without/ session replication: performance >> will be much better that way (and it's easier to configure). > > this is very interesting but somewhat of a concern as well. does > failover occur when one tomcat-and-web-app instance is taking a > long time serving one request? there are a few places/pages in my > web app that does some heavy lifting (reports that execute SQL > SELECT, and yes, I am using indexes along with statement caching, > etc...), and i've seen my app failover with a 404 error (i > currently only have one instance). It depends on how you configure things. It's usually the lb that makes that decision, so you configure it there. I would imagine that a good lb would be able to do things like "guess" the health of the backend-server and take it out of rotation if it's not healthy. mod_jk has a variety of health-checks that you can perform to decide when a Tomcat needs to be abandoned (perhaps temporarily). Your app fails-over to a 404? Something must be misconfigured. Or were you saying that your webapp returns a 404 if a query runs too long or something... that doesn't sound optimal. >> Well, if you can tolerate re-auth on failover, then there's >> nothing to do at all: simply enable sticky-sessions and let it >> happen. Failovers should be rare, anyway, right? > > sticky sessions sound nice and I would love to give it a try, but > honestly, i don't think the endusers want to have to re-auth on > failover. just today, I read on the atmosphere list that sticky > sessions are required for using atmosphere with/in clusters. i'm > definitely using atmosphere, but not using sticky sessions (or > clusters) yet. :( I think if you use async replication, you must use sticky sessions anyway, because otherwise you run the risk of having a user hit a different server before it has been updated from a previous request (on a different server). - -chris -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.17 (Darwin) Comment: GPGTools - http://gpgtools.org Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEAREIAAYFAlESjtAACgkQ9CaO5/Lv0PAQtwCgvzniTJG11eoJeOJcV3Gpnz6Y +UoAnRph0Qh6c8D5f9Mk0vHis3E1iMSy =GDk7 -----END PGP SIGNATURE----- --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
