[thredds] THREDDS 3.16: Memory issues

[Carlos Valiente]

John Caron wrote:
>> We're starting up Tomcat with -Xmx406m, in order to give it 4 GB of 
>> memory, but that does not seem to be enough. We've tried raising that 
>> limit to 6 GB, which is the total memory (physicall + virtual) 
>> available on that box, but it did not make any difference.
> 
> -Xmx406m = 406Mbytes, i assume you mean -Xmx4096m ??

Yep, typo

> Are you running 64-bit linux and JVM? Otherwise the JVM maxes out at 
> around 2 Gb.

Yep, it's the 64-bit one.

>> Are THREDDS memory requirements for aggregation higher than those 
>> figures, or are we perhaps doing something not too clever with our setup?
> 
> the aggregation itself should not be the problem. But how big is the 
> request?

For the variable that does not work (geopotential), these are the NetCFD 
files:

$ du -sch *
178M    MM_129_mon_1980.nc
178M    MM_129_mon_1981.nc
178M    MM_129_mon_1982.nc
178M    MM_129_mon_1983.nc
178M    MM_129_mon_1984.nc
178M    MM_129_mon_1985.nc
178M    MM_129_mon_1986.nc
178M    MM_129_mon_1987.nc
178M    MM_129_mon_1988.nc
178M    MM_129_mon_1989.nc
178M    MM_129_mon_1990.nc
178M    MM_129_mon_1991.nc
178M    MM_129_mon_1992.nc
178M    MM_129_mon_1993.nc
178M    MM_129_mon_1994.nc
178M    MM_129_mon_1995.nc
178M    MM_129_mon_1996.nc
178M    MM_129_mon_1997.nc
178M    MM_129_mon_1998.nc
178M    MM_129_mon_1999.nc
178M    MM_129_mon_2000.nc
178M    MM_129_mon_2001.nc
3.9G    total
$

The files for the one that does work are smaller:

$ -sch *
60M     MM_228_mon_1980.nc
60M     MM_228_mon_1981.nc
60M     MM_228_mon_1982.nc
60M     MM_228_mon_1983.nc
60M     MM_228_mon_1984.nc
60M     MM_228_mon_1985.nc
60M     MM_228_mon_1986.nc
60M     MM_228_mon_1987.nc
60M     MM_228_mon_1988.nc
60M     MM_228_mon_1989.nc
60M     MM_228_mon_1990.nc
60M     MM_228_mon_1991.nc
60M     MM_228_mon_1992.nc
60M     MM_228_mon_1993.nc
60M     MM_228_mon_1994.nc
60M     MM_228_mon_1995.nc
60M     MM_228_mon_1996.nc
60M     MM_228_mon_1997.nc
60M     MM_228_mon_1998.nc
60M     MM_228_mon_1999.nc
60M     MM_228_mon_2000.nc
60M     MM_228_mon_2001.nc
1.3G    total
$

 > The current opendap implementation requires the response to be
 > built in memory.

OK, I see. So I guess we need more memory in order to serve that kind of 
requests...

Thanks for your quick response, John!

C