Gradual loss of speed rate

  • Hi,
    I have always had transfer rate problems during an upload. When I upload a large file (an .iso file of 40GB for example), the transfer rate is about 100MB/s for 5 seconds, then progressively decreases to 20MB/s in 1 minute. Then it stagnates at 20Mo/s until the end of the copy.
    At first I thought it was a problem with the SMB protocol. I tried to change some parameters on the SMB protocol that I saw on several forum threads, but it did not work.


    I then tested the FTP protocol, and I have the same problem.


    My setup
    Erasmus 3.0.87
    Intel Celeron 2,3 Ghz
    RAM 8 GB
    RAID 5 software (4 x 1TB)


    For the FTP part, I tested FileZilla or Cyberduck, no change.
    Ideas ? thank you in advance :)

    OMV 3.0.87 (Erasmus)
    HP ProLiant MicroServer Gen8 G1610T - 8GB ECC - 4x Seagate BarraCuda 2TB (RAID5)


    Ride safe V

    Einmal editiert, zuletzt von Kamiz ()

    • Offizieller Beitrag

    Linux use available RAM to cache reads and writes. When both computers run out of caches, after a while, you get the best speed the chain of hardware and software can support sustained.


    You can try to replace parts to figure out what is the bottle neck. And try with different computers.


    Also as a filesystem fills up it typically slows down. Make sure you have at least 80% free.


    Try with a single empty ext4 HDD/SSD instead of the RAID5 array...


    Try nfs instead of ftp and smb.


    With really good hardware, software and good configuration you should be able to make the network the bottleneck. About 100 MB/s sustained. Then you can relax until you upgrade from GbE to 10GbE.

  • Hi,
    Here are the tests I just performed :


    Downloading from my server a file (present on a file host) to my RAID storage --> 15MB/s
    Downloading from my server a file (present on a file host) to a USB 3.0 hard drive --> 35MB/s


    I feel that I am limited not only by the speed of my RAID storage but also my processor. I sometimes have CPU peaks at 100%.
    Note that my internet access is not the issue, I download at 80MB/s from my PC.

    OMV 3.0.87 (Erasmus)
    HP ProLiant MicroServer Gen8 G1610T - 8GB ECC - 4x Seagate BarraCuda 2TB (RAID5)


    Ride safe V

    • Offizieller Beitrag

    It seems that native filesystems and single hdds connected via SATA III is the fastest. Using for instance RAID and/or NTFS and/or USB may cause bottlenecks.


    It would be interesting if you could test transferring to/from a hdd attached using SATA formatted as ext4. If you really want to get full speed, that might be the only way.


    I have small SBCs (Odroid HC2) with big single hdds connected using SATA III and formatted as ext 4. And I get close to 100 MB/s during sustained file transfers between HC2s, using nfs.


    I believe SMB/CIFS typically is about as fast as nfs. Almost...

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