Cluster.split Exit with no message

I’m running mothur 1.36.1 on an AWS EC2 with 16 processors, 122gb RAM, and 320gb storage.

Twice now I have been running cluster.split, had it run for several hours without error, then when it’s close to done it exits without an error message or making any note in the log file. There is no output, just about 60 .list and .temp files left in the directory.

Below is the last command run.

mothur >
cluster.split(fasta=current, count=current, taxonomy=current, splitmethod=classify, taxlevel=4, cutoff=0.15)
Using stability.trim.contigs.subsample.unique.good.filter.unique.good.precluster.denovo.uchime.pick.pick.count_table as input file for the count parameter.
Using stability.trim.contigs.subsample.unique.good.filter.unique.good.precluster.pick.pick.fasta as input file for the fasta parameter.
Using as input file for the taxonomy parameter.

Using 16 processors.
Using splitmethod fasta.

This is the last thing in the log file before it exited:

Reading stability.trim.contigs.subsample.unique.good.filter.unique.good.precluster.pick.pick.fasta.0.dist
Reading matrix: |||||||||||||||||||||||||||||||||||||||||||||||||||

Clustering stability.trim.contigs.subsample.unique.good.filter.unique.good.precluster.pick.pick.fasta.0.dist
Cutoff was 0.155 changed cutoff to 0.07

Reading stability.trim.contigs.subsample.unique.good.filter.unique.good.precluster.pick.pick.fasta.2.dist

It quit at the same spot both times.

I suspect you have too many large distance matrices being clustered at the same time. Could you drop processors down to 4?