When I asked this question I had in mind a few potential downsides to one 8 GB Tomcat. One is memory leaks: if Tomcat starts to leak memory (not sure if this happens too often, if ever, but I'm speaking purely hypothetically) then you'd rather not want your single Tomcat to eat up all the memory. If you had two Tomcat instances running the exact same application, then the memory leak is only affecting up to 4 GB?
The other is high-availability - if you have a huge 8 GB box and it's because you decide not to have 4 x 2 GB smaller boxes, then you definitely cannot get high-availability against hardware issues - but say you're pushing out an upgrade to the application (i.e. the WAR file). If you have two Tomcats, couldn't you bring one down while the other continues to serve requests, push out the upgrade, bring it back up, then do the same with the other application? With only one instance, you must have downtime right? The last is at the following link, several performance graphs for Linux show a slight or sharp decrease in performance for a given Tomcat instance beyond a certain number of users! Why is this? Wouldn't these diminishing returns, if true, severly cripple one 8 GB instance serving 2*n users compared to two 4 GB instances serving only n users? http://www.webperformanceinc.com/library/reports/windows_vs_linux_part1/index.html Christopher Schultz-2 wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Lightbulb, > > lightbulb432 wrote: >> If you have a gigantic server with something like 8 GB of memory, what >> would >> be the best way to run Tomcat 6 on it? One instance, multiple instances, >> or >> divide it up into two or more virtualized servers each with one instance? > > Unless you have concerns about stability of TC6 or your own application, > one big JVM with a ton of threads would be my recommendation. > Virtualization or multiple TC instances only adds overhead with no other > real benefit. (If you run multiple applications, multiple TC instances > might make sense). > >> Is Tomcat meant to run as one instance with that much memory, or is it >> optimized for a different amount of memory? > > Tomcat shouldn't care. I think that thread synchronization is faster > than full context switching, but that can be very sensitive to the > platform, OS, and tuning parameters you might have (in the OS). Java is > perfectly happy to run with 8GB. > >> I realize with the options I mentioned above there are implications >> regarding high-availability and performance, but I'm not sure exactly >> what >> they'd be. Perhaps someone with more knowledge of this kind of stuff >> could >> comment. > > If you trust your operating system (I would trust any UNIX and UNIX-like > OS, and Windows is somewhat dependable if you don't ask it to do too > many things), then a single instance of the OS on a lot of hardware is > just fine: go for it. > > If you are concerned about your OS's stability, then by all means run > multiple instances of the OS and load balance between. From a strict > performance standpoint, less is more, so stick to one OS and one Tomcat > instance on that big, fat machine. > > - -chris > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.7 (MingW32) > Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org > > iD8DBQFGqOyq9CaO5/Lv0PARAlTDAJwKFLgizNh/MatDmEupjdLvLvvDWgCfbHSj > XLO50tctVgV5w+N/qwYYZEQ= > =DJLh > -----END PGP SIGNATURE----- > > --------------------------------------------------------------------- > To start a new topic, e-mail: users@tomcat.apache.org > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > > -- View this message in context: http://www.nabble.com/Tomcat-with-8-GB-memory-tf4149367.html#a11817605 Sent from the Tomcat - User mailing list archive at Nabble.com. --------------------------------------------------------------------- To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
