I can think of a couple of possible explanations:
-
Other applications on your system are using so much memory that there isn’t 300Gb available right now.
-
There could be a resource limit on the per-process memory size. You can check this using
ulimit. (Note that according to this bug, you will get the error message if the per-process resource limit stops the JVM allocating the heap regions.) -
It is also possible that this is an “over commit” issue; e.g. if your application is running in a virtual and the system as a whole cannot meet the demand because there is too much competition from other virtuals.
A couple of the other ideas suggested are (IMO) unlikely:
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Switching the JRE is unlikely to make any difference. I’ve never heard or seen of arbitrary memory limits in specific 64 bit JVMs.
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It is unlikely to be due to not having enough contiguous memory. Certainly contiguous physical memory is not required. The only possibility might be contiguous space on the swap device, but I don’t recall that being an issue for typical Linux OSes.
Can anyone please suggest a solution/workaround?
-
Check the
ulimit. -
Write a tiny C program that attempts to
malloclots of memory and see how much that can allocate before it fails. -
Ask the system (or hypervisor) administrator for help.