[geeks] Upper Memory Limit - Java

[Brian Dunbar]

> On Tue, Jan 29, 2008 at 01:56:46PM -0800, Brian Dunbar wrote:
>
> | We have an EDI program (it's new) that blows up when 'many large files'*
> | are run through it.
> |
> | But I'm not here to complain about that.  During troubleshooting the
> | vendor rep mentioned that Java has an upper memory limit and you can't
> | allocate any more memory to it than X.
> |
> | Indeed we're giving the JVM 3850m of ram on startup
> |
> | /vendor-dir/bin/java -Xms3850m -Xmx3850m
> |
> | And it won't start with any more than that.
> |
> | But .. an upper memory limit on Java?  I can believe there is a point
> past
> | where it's simply not wise to allocate ram but .. is she mis-informed?
>
> No, she's not.  Though it's generally not about `not being wise' -- it
> just breaks.
>
> 32 bit JVMs tend to blow up with -Xmx set at 2 GB or higher.  Of
> course, in general, on a 32 bit platform, no process can allocate more
> than 4 GB of memory, and your OS has to jump through some hoops to
> even have that much memory available.
>
> For 64 bit JVMs, I don't know.  I would expect any hard coded memory
> limits to be huge, but I haven't really done much with them.
>
> I'm surprised you can get up to 3850m -- but no higher.  Which JVM is
> that?

1.5

> What OS, platform?

# uname -a
SunOS hostname.company.com 5.10 Generic_118833-36 sun4u sparc
SUNW,Sun-Fire-V240

-- 
Brian Dunbar