On 18/11/2011 9:08 PM, Jan Just Keijser wrote:
David Holmes wrote:
Hi Jan,
You can use the environment variable _JAVA_OPTIONS to set -Xmx.
The other option is to use your own wrapper script for launching the
VM that contains whatever flags you need.
we would really like to avoid a wrapper script. The env var
_JAVA_OPTIONS is a nice workaround, although I'm not thrilled about the
fact that I now see
$ java -version
Picked up _JAVA_OPTIONS: -Xmx256M
java version "1.6.0_20"
OpenJDK Runtime Environment (IcedTea6 1.9.10)
(rhel-1.23.1.9.10.el5_7-x86_64)
OpenJDK 64-Bit Server VM (build 19.0-b09, mixed mode)
Is there any way to get rid of that message?
No - we've complained about it ourselves. I guess it is trying to ensure
that any implicit options picked up from _JAVA_OPTIONS is made explicit
but it is somewhat annoying.
David
thx,
JJK / Jan Just Keijser
On 17/11/2011 11:28 PM, Jan Just Keijser wrote:
hi all,
I would like to report an issue with OpenJDK 1.6 (and Oracle Java 6u29)
that we have run into on our grid computing farm:
the latest&greatest worker nodes have 12 cores and 48 GB of RAM ; we
offer a maximum 12 jobs slots on these worker nodes, in order to
accomodate small and large jobs (users can requests 1 - 12 cores). To
ensure that the different jobs don't interfere with each other we also
set a VMEM limit for each job slot. The current VMEM limit is 48 / 12 =
4 GB RAM per job slot. Each single core job that starts has a 'ulimit
-v' of 4,000,000 .
On these boxes OpenJDK 'java' refuses to start:
$ java -version
Error occurred during initialization of VM
Could not reserve enough space for object heap
Could not create the Java virtual machine.
After some debugging I found that this is caused by the default maximum
heap size which java allocates: it scans /proc/meminfo to extrac the
amount of RAM installed and divides it by 4 ; an 'strace' shows that
indeed 'java' tries to do an 'mmap' call for 12 GB of RAM !
A work around is to always specify '-Xmx2GB' or something similar but
this does not work for all software that we use , plus , I find it
annoying that I have to tell this to all my users.
What I would like to see is a system-wide setting for the initial
maximum heap size, so that
java -version
"just works" . Is this possible?
thanks in advance,
JJK / Jan Just Keijser
