Hello,
we are using Ray to assemble a metagenomics sample coming from a single
Illumina HiSeq lane (around 32 Gigabases of sequence with 100bp paired end
reads). We have prepared the taxonomy and bacterial genomes sequences using
the script available on the Ray repository. We are running the analysis on
a single server with 48 cores and 512 Gb of RAM and the process is running
since 24h. Here is the command line used:

mpiexec -n 40 Ray
-k 31
-p /metagenomics/sample1/cleanReads/sample1_R1_clean.fastq
/metagenomics/sample1/cleanReads/sample1_R2_clean.fastq -serach
/ray_taxo_file/NCBI-taxonomy/NCBI-Finished-Bacterial-Genomes
-with-taxonomy /ray_taxo_file/NCBI-taxonomy/Genome-to-Taxon.tsv
/ray_taxo_file/NCBI-taxonomy/TreeOfLife-Edges.tsv
/ray_taxo_file/NCBI-taxonomy/Taxon-Names.tsv

The problem is that we are seeing a high memory usage, basically Ray is
taking all the 512 Gb of RAM, which is something unexpected since in the
Ray Meta paper it is said that for a test sample of this size (1 HiSeq
lane) it used ~ 2 Gb of memory on 128 cores. So we expected the memory
usage to be around 256 Gb of RAM, assuming the memory requested is
proportional to the size of the input and not to the number of cores used.

Is it normal to have Ray using so much memory or have we done something
wrong when we launched the process ?

It is the first time we try using Ray so any help or advise is more than
welcome!

Many thanks

-- 

Francesco
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