Is there any contract between Heap size and PermGen Space

satyendra2161 Jun 9, 2011 4:17 AM

I my server Ram is 16GB but when

1. I tried to set max heap size to 2048MB in run.bat file and when started jboss server it thrown exception as "Could not reserve enough space for object heap" it accepted max 1336 mb.

2. and also JBoss server did not accept more than 128MB PermGen space but when I reduce the heap size from 1336 to 1024 it accepted PermGen space to max 256MB.

Please let me know the reason when I have enough memory why it is not accepting heap size as 2048 and what is contract between heap size and PermGen space as reducing heap size helped PermGen space to increase.

1. Re: Is there any contract between Heap size and PermGen Space

pgmjsd Jun 9, 2011 8:16 PM (in response to satyendra2161)

That would depend on the JVM and the OS, which you have not specified... So probably nobody will answer your question.

FWIW, we (my company) run 700M heap, 128M perm gen, 32bit Sun/oracle 1.6.0_x JVMs on centOS 5.1, 64bit. No problems running quite a few of those on one 16gb ram box.
Actions
2. Re: Is there any contract between Heap size and PermGen Space

wdfink Jun 10, 2011 2:17 AM (in response to satyendra2161)

As Joshua wrote it depends to your OS and JVM.
So please post information about this.

I suppose you try a 32Bit JVM, for this 2GB is often the maximum.
The JVM's memory contains PermGen, ThreadStack, Heap and some more.
All together can not break the maximum.

If so try a 64Bit VM if your OS is a 64Bit system
Actions

Go to original post