Read speeds from WHS shares to (MacOSX) client machines unacceptably slow RRS feed

  • Question

  • Hi:

    My current WHS PP2 system is an Athlon XP2600+, 1GB RAM, 1x320GB IDE as primary disk and 2x1TB SATA added to the storage pool. My network is wired 100Mbps. I have like 300GB of movies in a duplicated folder and 20GB of Music also duplicated. The software share contains 20GB of non duplicated data.

    The issue I'm having happens whenever I copy a file from a Share, no matter if it's duplicated or not, to any of my clients (one running the last release of Leopard and the other the last release of Snow Leopard). The speed of such transfers (read) is around 1.5MB/s! Logging in the WHS via Remote Desktop shows CPU usage tending to 0% and network usage percentage under 20%, the disk led blinking slightly each 2 seconds. If instead, and here comes the magic, I login into WHS via RD, map the drive of any of my clients and copy the same file the other way around, from WHS, the speed is above 8-10MB/s, as expected.

    What could be the reason of such behavior?

    Thanks a lot in advance.
    Monday, October 12, 2009 7:32 PM


  • Fixed. 

    sudo sysctl -w net.inet.tcp.delayed_ack=0

    It seems that MacOSX delays the ACKs to the server, causing it to slow down incredibly much.


    I hope it can help somebody.
    Monday, October 12, 2009 8:49 PM