I have to wonder what one does if they have a CF server that requires more than 1.8gb RAM for the JVM, say u have some big heavy site sthat do a lot of caching of big files/queries?
-----Original Message----- From: Dante Orlando [mailto:[EMAIL PROTECTED] Sent: 22 May 2006 19:41 To: CF-Talk Subject: Re: MaxHeapSize + MaxPermSize Thanks for all of your replies. First of all, I was really just looking for the "whys" rather than any particular recommendation on what values to set these params to. As far as the permanent generation being part of the heap, I have been able to verify that the permenent generation (i.e. -XX:PermSize and -XX:MaxPermSize) is *separate* from the object heap (i.e. -Xms and -Xmx). See the following diagram from Sun: http://java.sun.com/docs/hotspot/gc1.4.2/fig4.gif which was taken from http://java.sun.com/docs/hotspot/gc1.4.2/ .....also see Moazam Raja's explanation in the following blog entry: http://www.unixville.com/~moazam/stories/2004/05/17/maxpermsizeAndHowItRelat esToTheOverallHeap.html Rob: I too have heard the explanation about the object heap needing to occupy a contiguous block of memory, and that Windows is only able to meet that requirement up to 2GB. Incidently, this is also why the /3GB flag is useless on Windows at least as far as a jvm process is concerned. The thing is that even with these restrictions I thought you could still get a jvm process that was closer to 2GB, as opposed to the 1.6GB I'm seeing in my tests. There is even a ColdFusion TechNote that suggests that the maximum value should be more like 1.8GB ( http://www.adobe.com/cfusion/knowledgebase/index.cfm?id=tn_19359). It turns out that, if you dig a little deeper, the maximum contiguous memory block you can get in Windows is actually a bit less than 2GB because of the way some of the system DLLs are loaded, and the fact that Windows implements two "standard" 64KB holes in the virtual address space, one at the bottom, and another near the 2GB boundary. I guess I'm beginning to answer my own question... Anybody else have any additional thoughts on the matter? thx, -dante ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| Message: http://www.houseoffusion.com/lists.cfm/link=i:4:241157 Archives: http://www.houseoffusion.com/cf_lists/threads.cfm/4 Subscription: http://www.houseoffusion.com/lists.cfm/link=s:4 Unsubscribe: http://www.houseoffusion.com/cf_lists/unsubscribe.cfm?user=11502.10531.4 Donations & Support: http://www.houseoffusion.com/tiny.cfm/54
