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JVM Heap Settings

srinivma
Occasional Advisor

JVM Heap Settings

Hi,
Whenever I try to run a JBoss server(4.2.3.GA) installed on HP-UX with JVM Heap Settings of more than 3.5GB for 32 bit JVM Mode, JBoss does not startup and no logs -server or boot log files in Jboss/deploy folder are generated . I wonder what is happening? I tried doing ps -ef|grep java but it seems the java process is not even loaded in HP-UX.

I even searched in syslog and eventlog still no luck. Lastly, I searched for core dump files in PWD and in $USER_HOME directory, but there were no files generated.

Please help me as to what is happening here? Are there any other log files that I can look into? I expected it to crash whenever I am giving higher heap settings than 3.5 GB or atleast some heap dump or OutOfMemory error.
14 REPLIES
Dennis Handly
Acclaimed Contributor

Re: JVM Heap Settings

What are your values of the kernel parms maxdsiz and maxdsiz_64bit? What OS version?
srinivma
Occasional Advisor

Re: JVM Heap Settings

CPU info:
1 Intel(R) Itanium 2 9100 series processor (1.67 GHz, 18 MB)
666 MT/s bus, CPU version A1
2 logical processors (2 per socket)

Memory: 16363 MB (15.98 GB)

Firmware info:
Firmware revision: 04.11
FP SWA driver revision: 1.18
IPMI is supported on this system.
BMC firmware revision: 5.24

Platform info:
Model: "ia64 hp server rx2660"

OS info:
Release: HP-UX B.11.31
Machine: ia64
Aneesh Mohan
Honored Contributor

Re: JVM Heap Settings

Hi,

Please post the output of the below command too.

#kctune -q maxdsiz
#kctune -q maxdsiz_64bit
srinivma
Occasional Advisor

Re: JVM Heap Settings

kctune -q maxdsiz

Tunable Value Expression Changes
maxdsiz 1073741824 Default Immed


kctune -q maxdsiz_64bit

Tunable Value Expression Changes
maxdsiz_64bit 4294967296 Default Immed
Dennis Handly
Acclaimed Contributor

Re: JVM Heap Settings

>Aneesh: kctune -q maxdsiz

kctune(1m) doesn't use -q, you want:
kctune maxdsiz maxdsiz_64bit
srinivma
Occasional Advisor

Re: JVM Heap Settings

kctune maxdsiz maxdsiz_64bit

Tunable Value Expression Changes
maxdsiz 1073741824 Default Immed
maxdsiz_64bit 4294967296 Default Immed
Aneesh Mohan
Honored Contributor

Re: JVM Heap Settings

Hi

Current maxdsiz is only 1GB , increase it to 4 Gb.

Regards,
Aneesh
srinivma
Occasional Advisor

Re: JVM Heap Settings

Thanks for info , but what is the HP-UX command for increasing it to 4GB?
Dennis Handly
Acclaimed Contributor

Re: JVM Heap Settings

>what is the HP-UX command for increasing it to 4GB?
# kctune maxdsiz=4GB
srinivma
Occasional Advisor

Re: JVM Heap Settings

Thanks.. I will try that out and let you know. One last thing, is it also possible to increase dsize for 64 bit because I am facing the same issue mentioned earlier in the post for 32 bit JVM i.e. that is I am facing similar issue if the JVM Heap size is more than 13 GB.
Don Morris_1
Honored Contributor

Re: JVM Heap Settings

maxdsiz_64bit is the corresponding tunable to set the hard limit for the 64-bit process heaps.
srinivma
Occasional Advisor

Re: JVM Heap Settings

What is the maximum size supported by maxdsize_64 bit?
Aneesh Mohan
Honored Contributor

Re: JVM Heap Settings

Hi,

maxdsiz and maxdsiz_64bit
maxdsiz and maxdsiz_64bit specify the maximum data segment size, in bytes, for an executing process.

Acceptable Values:
maxdsiz for 32-bit processors:

Minimum
0x400000 (4 Mbytes)
Maximum
0x7B03A000 (approx 2 Gbytes)
Default
0x4000000 (64 Mbytes)
maxdsiz_64bit for 64-bit processors:

Minimum
0x400000 (4 Mbytes)
Maximum
4396972769279
Default
0x4000000 (64 Mbytes)


But if you set these values too high then system can face huge paging ,becoz any memory eating process can allocate as much virtual memory as it could.


Regards,
Aneesh
Dennis Handly
Acclaimed Contributor

Re: JVM Heap Settings

>What is the maximum size supported by maxdsize_64 bit?

More than the swapspace you have. It is a 64 bit value.
You could start with 13 GB.