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  • SRAtoolkit - prefetch and fastq-dump problems

    I'm attempting to download a ton of protected GTEx data using sratoolkit.

    Using fastq-dump alone for accession numbers is painfully slow. My Mac is taking 2-4 hours to get each ~3Gb file.

    e.g. This took 3.4GB file took 2:23:19 to download:
    Code:
    ~/sra-toolkit/bin/fastq-dump --bzip2 --split-spot --clip --skip-technical --dumpbase --readids SRR1397673
    Prefetch has worked better; running both the html download (~30min) and fastq-dump from the prefetched .sra (~1hr) is much faster than fastq-dump alone. Unfortunately, I can't get prefetch to use Aspera.
    (GTEx SRR#s have been changed to a publicly available SRR# for the examples below.)

    I think the aspera problem is prefetch-specific; tests using the following code resulted in a nice, speedy download.
    Code:
    ~/Applications/Aspera\ Connect.app/Contents/Resources/ascp -T -l150M -i ~/Applications/Aspera\ Connect.app/Contents/Resources/asperaweb_id_dsa.putty [email protected]:/sra/sra-instant/reads/ByRun/sra/SRR/SRR292/SRR292241/SRR292241.sra .
    However, things went much less smoothly using this:
    Code:
    ~/sra-toolkit/bin/prefetch -t ascp -a "~/Applications/Aspera\ Connect.app/Contents/Resources/ascp | ~/Applications/Aspera\ Connect.app/Contents/Resources/asperaweb_id_dsa.openssh" SRR292241
    I ended up with this error:
    2017-08-09T22:54:52 prefetch.2.8.2: 1) Downloading 'SRR292241'...
    2017-08-09T22:54:52 prefetch.2.8.2: Downloading via fasp...
    2017-08-09T22:54:53 prefetch.2.8.2 err: process failed while waiting process - ascp failed with 1
    2017-08-09T22:54:54 prefetch.2.8.2 err: process failed while waiting process - ascp failed with 1
    2017-08-09T22:54:54 prefetch.2.8.2: fasp download failed
    2017-08-09T22:54:54 prefetch.2.8.2: 1) failed to download SRR292241

    I've tried adding the -X 200G flag to circumvent the error, without success.

    Any suggestions for speeding up my download from SRA/dbGaP?

  • #2
    Some solutions

    If anyone else has run into this problem, I've found a couple of things that seem to help.

    1) If you have similar problems with prefetch or fasp downloads fail:
    Simply remove the -a and -t flags. When I dropped the -t flag alone, prefetch would fail to download via fasp and default to html. When I also removed the -a flag, prefetch successfully downloaded via fasp.

    2) If running fastq-dump runs painfully slow (before or after prefetching):
    I strongly recommend using parallel-fastq-dump.

    Comment


    • #3
      If you want predictable fastq-dump performance... use local data sources.

      1. Forget about the wi-fi. Use only wired network (suitable docking station with ethernet if on macbook).

      2. Download the sra files to the DAS or good NAS (use aspera, do it over the weekend if possible and be patient).

      3. Than mount in on the mac/linux box and give SRA files to the fastq-dump actual SRA files.

      Comment

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