-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi Noah,
On 14.03.11 um 21:27, Noah Cutler wrote: > So, given that a running 32-bit JVM on Linux will require at least 1GB > RAM, total memory usage will not be JVM footprint * num instances, but > rather, JVM footprint + num instances? Actually, the 1GB are virtual memory usage, not everything is allocated in the physical memory. I'd say it is roughly: num instances * (JVM not shareable + JVM heap&perm) + JVM shareable. JVM not shareable could be around 200-300MB. What heap sizes do you expect? The figures I gave for Tomcat were taken directly after startup. Because Tomcat starts additional threads for the connector thread pools these could increase (maybe 50MB instead of 5MB), and request processing needs some memory. > The use case is transferring 20 client sites from LAMP stack to JVM + > Tomcat 7 + MySQL + a Groovy.lang web framework I developed. > > Ideally I would separate client sites into tomcat instances, so as to > isolate them from each other (i.e. redeploy/restart without affecting > other instances), but that hinges entirely on the memory footprint. You have to include the memory footprint of your applications into the calculation. If you configure small heap sizes the risk of getting OutOfMemoryErrors increases. If you deploy more than one application in your tomcat instances, average usage of heap memory, threads and database connections could be better. > I have 16GB RAM available but was only planning on allocating 4-6GB RAM > for this project. Only a couple of the sites in question do significant > load (read: have been running on LAMP stack with 2GB RAM for several > years without issue) I'd try a mixed approach: Run some tomcat instances with more than one application. Some restarts can be avoided by using hot deployments. The MemoryLeakPreventionListener [1] helps to check if your applications trigger some known memory leaks. That may fit your needs. I'm afraid it is very hard (or impossible) to start with an optimal configuration. You will have to make an educated guess (usually configure more ressources than necessary), monitor the resource usage, and adapt the configuration to your needs. [1] http://tomcat.apache.org/tomcat-7.0-doc/config/listeners.html Regards, - -- Thomas Freitag -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iEYEARECAAYFAk1/LNAACgkQGE5pHr3PKuVkTwCeJLZkrBKq9yVkEmenQUV+ItkO OcUAn3sznmYn/GTpbLospwQ30Kp7Ly/g =+pCj -----END PGP SIGNATURE----- --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
