Raspberry 3B+, Speedproblem, slowing down

  • Hi,
    I finally managed to establish an FTP-Sever at my Raspberry.


    (New Raspbian, installing OMV, Partition on my SD-Mircorcard (100 GB))


    Now I started to sync (via the software "Goodsync") my office files on my PC, Windows 10, with the Raspberry. At first its running with 60, 80 or so MB/sec but within 15 seconds or so the speed slows down to 0,5 - 6 MB/s. If I stop the sync process and start again, the same slowdown occurs. This is disappointing, cause the sync process between PC/Fritzbox is about the same speed; so no need of an raspberry.


    Why is that? I checked on the CPU temperature. It stays between 50 and 59 C.


    What can I do?

  • Yes, its not an USB-Stick. First I installed Rasbian and then OMV. Afterwards I created with gparted a third partition on the SD-Card and formatted it (mkfs.btrfs -f /dev/mmcblk0p3).


    What speed should this configuration have?

  • What speed should this configuration have?


    No idea. I don't trust Raspbian (same with every other 'hardware vendor provided OS image' approach we see on all those single board computers) and so I don't use it.


    The 'official' OMV image for Raspberries relies on true upstream Debian armhf and the Armbian build system: https://sourceforge.net/projec…/Raspberry%20Pi%20images/


    With this image and without further tweaks you should see steady 10-11 MB/s. If you edit /etc/rc.local to comment out the ethtool command that limits the RPi 3 B+ to Fast Ethernet due to the crappy Gigabit Ethernet implementation then you'll see +20MB/s. If you follow the usual guides to overclock the SD card on the RPi and you use one of the appropriate SD cards you'll max out at 35-37 MB/s (the latter not recommended -- data corruption or silent bit rot aren't fun. Good to see you're already using btrfs since being a checksummed filesystem notifying you of data corruption once it happened)

  • I would prefer to install the official OVM image. But in truth I want to install an FHEM server as well. And I dont know if this is possible on the official OVM image/linux. And if yes, I dont know if I can manage the installation of FHEM without any help, cause I am a n00b at linux.
    Do you know something about FHEM on OVM image?

  • Do you know something about FHEM on OVM image?


    Not really. But if FHEM runs on Debian then it will run on the OMV image as well since the OMV image is just 'Debian + OMV' (plus a lot of NAS related tweaks).


    Raspbian is also based on Debian and 99% of stuff is exactly the same. One difference that often causes troubles is that tutorials for the RPi always assume Raspbian specifics like an user account called pi with a homedir /home/pi, and inexperienced users then struggle to follow such tutorials since with plain Debian there's no need to name the account pi and put the data into this specific location.

  • Hello, good evening,


    I have installed the original OMV image and I have commented out ethtool (At least I think I have done it the right way).


    Measurements with iperf:


    215 MBits/sec or 26 MB/sec


    I think this might be a good result, although the USB chip should do something around 300 MBits as I have read. Is the transferred data via iperf saved to the SD card as well and included in anyway in the measurements of iperf?


    Nonetheless my sync programm 'goodsync' shows roundabout 4-10 MB/sec upload speed to the raspberry from a windows 10 pc. I dont like that result. Maybe the measurement of the 'goodsync' is not correct. Or it might be, that the upload of tons of small files reduces the upload speed?


    Now, is there another method to test the transfer speed (and writing process to the SD-Card)? I uploaded some data to the raspberry with filezilla, but I could not find the upload speed in real time.


    Suggestions?


    Thank you very much.

  • Is the transferred data via iperf saved to the SD card as well and included in anyway in the measurements of iperf?

    No, that's just networking without any storage activity involved. And yes, a bunch of small files takes longer to transfer than huge files. And of course storage performance is also important so that needs to be tested individually first. Not with dd or hdparm (since generating almost always numbers without meaning) but testing through a bunch of different block sizes and both sequential and random IO with for example iozone -e -I -a -s 100M -r 4k -r 16k -r 512k -r 1024k -r 16384k -i 0 -i 1 -i 2 -- see https://github.com/ThomasKaise…_and_A2_rated_SD_cards.md


    But since all of this happens on a Raspberry Pi it's pointless. Worst choice possible for anything related to network and/or storage: https://forum.openmediavault.org/index.php/Thread/25744

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