Not enough memory for depth of Coverage as single thread
if I run depthOfCoverage without -nt it crashes somewhere in Chromosome 11 with
ERROR MESSAGE: An error occurred because you did not provide enough memory to run this program. You can use the -Xmx argument (before the -jar argument) to adjust the maximum heap size provided to Java. Note that this is a JVM argument, not a GATK argument.
This can't be the real reason since it only uses around 15% of our 512 Gb.
If I try with -nt 48 it finishes even though it loops over the last interval for about 90 minutes before it really stops. And I can't produce the interval files. So it is not an option for us.
I tried with GATK 3.7 and 3.8 on a local Server. The NextSeq run is composed of 25 panel diagnosics and 3 whole Exome samples.
Is there something we can try or is there information if this happens when using too many samples or to large bam files? Does depthOfCoverage limits itself? Why is there a difference between running with -nt and without?
Thanks in advance,