-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 André,
On 5/16/12 5:50 AM, André Warnier wrote: > Nobody can answer that question in the absolute. It all depends on > how much memory your Tomcat instances really need (Really, your webapps, not Tomcat). > to run the applications you put it them, for the number of requests > you expect to be handled. And won what else on that machine needs > memory, and how much memory that machine has. > > Tomcat can run in as little as 512KB (or less). The other end is > unlimited.. Tomcat itself can run in like a 12MiB heap, depending on the JVM version. We ran in production for years using a miniscule (for Java-based webapp) 64MiB heap. > The benefit of a 64-bit OS compared to a 32-bit OS, is that you > can allocate more memory *per process*. A drawback of running an > application in 64-bit mode - compared to running the same in 32-bit > mode - is that under 64-bit mode, some things will use up 64 bits > instead of 32 bits. So you roughly use about 30% more memory, to > run the exact same application. But that also depends very much on > the application. > > In other words : try it and see. Also, there are lots of reasons to run multiple JVMs, even on the same physical machine. For instance, you might want to improve the robustness of your webapp by being able to restart one of the JVMs if something goes wrong (e.g. OOME) or even to upgrade your webapps(s) with zero downtime. (This of course assumes that you can run two different versions of your webapp simultaneously including all dependencies like database structure, etc.). Or, maybe you want to run different webapps under different JVM versions for some reason. We currently run all our productions webapps in their own Tomcat instances with independent JVM versions, etc. It provides complete isolation between webapps at the cost of memory. Memory is cheap, and our webapps don't need a lot of it. - -chris -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.17 (Darwin) Comment: GPGTools - http://gpgtools.org Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk+zxSQACgkQ9CaO5/Lv0PCRUgCdEfaEQt5CjJ9qVIHA1jyrqaqC M6UAnRIDcBSfG7gRBHsxvFSH5UISLl2k =vv+b -----END PGP SIGNATURE----- --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
