File transfers to OMV drop in speed after ~1GB

  • Bus 005 Device 002: ID 152d:0551 JMicron Technology Corp. / JMicron USA Technology Corp.

    Smells like a JMS551 which should be the slower predecessor of JMS561 (USB-to-SATA bridge with 2 port SATA PM). Stange combination since this would mean that's two cascaded SATA PMs inside this Fantec thing. Anyway: it's a USB3 SuperSpeed connection (Port 1: Dev 2, If 0, Class=Mass Storage, Driver=usb-storage, 5000M) but performance sucks obviously. In your case it seems NAS transfers are fast until filesystem buffers (RAM) are full and then contents are flushed to disk.

  • These things can start to throttle based on access pattern. Your two iozone tests both seemed to test an USB drive since reported values are a bit too high for SD card or eMMC (or maybe you run off a really good high capacity eMMC module)?
    Anyway: the mode to test with iozone is


    Code
    cd /path/to/mountpoint
    iozone -e -I -a -s 1000M -r 128k -r 1024k -r 16384k -i 0 -i 1


    This will test sequential transfer speeds with three different block sizes (128KB, 1MB, 16MB) and will also show throttling effects if an USB thumb drives starts to heat up and then slows down after some time. That's why we test with several block sizes of increasing size since normally the larger the block size the higher the transfer speeds. If performance decreases you know the thumb drive throttles to prevent overheating.


    I am using a class 10 SD card. My test drive is a USB 3.0 thumb drive formatted to ext4. The actual drive I am trying to use for this is a USB 3 ProRAID array in RAID 0 which is my current media drive attached directly to my router, but I wanted to do a few test runs with OMV before moving it over. I went ahead and mounted up the RAID drive this morning and ran the iperf test. Here are the results. The drive is currently formatted NTFS but I plan to reformat it to EXT4 when I can back everything up off of it first (usually takes about 48 hours for 6TB of data).



  • It's iozone instead and while this 'RAID' performs poorly in the end once you exchange your thumb drive with this thing you'll most probably end up with +80MB/s NAS performance in both directions.

    Yup, that's what I meant lol. So backed up all my data yesterday and last night to some other drives. This morning I reformatted the RAID drive to EXT4 through the OMV interface and started moving the files back. Getting consistent 80MB+ speeds on writing back to the drive. Larger files are even moving at 110-112MB through almost the whole file so it's damn near maxing out and I'm happy. Thanks for the help on sorting out my issue.

Jetzt mitmachen!

Sie haben noch kein Benutzerkonto auf unserer Seite? Registrieren Sie sich kostenlos und nehmen Sie an unserer Community teil!