[Facts] network speed difference by increasing the mtu (maximum transfer unit)
system: 2x NICs with 10 Gb/s SFP+ ports connected with fibre-cable (Intel 82599, Mellanox MNPA19-XTR) test-software: iperf3-3.1.3 result: +5% #with mtu=1500 [SUM] 0.00-10.00 sec 11.0 GBytes 9.45 Gbits/sec sender [SUM] 0.00-10.00 sec 11.0 GBytes 9.40 Gbits/sec receiver #with mtu=9000 … Continued
[Howto] manually download kernel headers / sources in FreeBSD
download via svn or svn-lite: #command to download the complete FreeBSD source-files svnlite checkout https://svn.freebsd.org/base/releng/11.0/ /usr/src/ #command to download only the FreeBSD kernel/header source-files svnlite checkout https://svn.freebsd.org/base/releng/11.0/sys/ /usr/src/sys
[Howto] update the firmware of HP Enterprise Mellanox ConnectX-2 EN NIC (671798-001)
Disclaimer: All liability is excluded. Be careful, you can brick your card. Important: you can’t use the firmware from HP 516937-B21 for the 671798-001, because all downloadable firmwares are for the 2-Port Version or for the wrong Board-Revision. So … Continued
[Howto] update the firmware of HP Enterprise SAS Expander (468406-B21)
Disclaimer: All liability is excluded. Be careful, you can brick your card. prerequisites: an Host-Bus-Adapter (e.g. LSI 9210-8i) #install the HBA and the SAS-Expander into your PC and connect both with an SFF8087-cable #download the needed tools (e.g. Debian … Continued
[Howto] migrate a bootable filesystem from UFS to mirrored ZFS
for example we use 2 new HDDs, which are called ada0 and ada1. Quick steps: you have to create 2 partitions on the new disks (1st for the zfs-bootloader, 2nd for the zfs itself) you have to set the first … Continued
[Howto] bond network interfaces in FreeBSD 10 (LAGG)
insert into /etc/rc.conf the following code: (e.g. 4x Intel NICs bond together in LACP-Mode) # tested under FreeBSD v10.x and v11.x ifconfig_igb0=”up” ifconfig_igb1=”up” ifconfig_igb2=”up” ifconfig_igb3=”up” cloned_interfaces=”lagg0″ ifconfig_lagg0=”laggproto lacp laggport igb0 laggport igb1 laggport igb2 laggport igb3 192.168.0.1 netmask 255.255.255.0″
[Facts] introduction for maxim integrated DS2482-800 chip (i2c to 1-wire interface)
short facts: supported i2c-speeds: Standard-Mode (100 kHz) and Fast-Mode (400 kHz) supported 1wire-speeds: Standard-Mode and Overdrive-Mode 8 independent 1-wire channels (1 active channel per-time, default-channel = 00) 8 possible i2c-adresses (selectable via 3 pins) supports 1-wire signal-optimization (3 possiblities: normal-resistor, … Continued
[Howto] set the speed of I²C-Bus from Raspberry Pi
to set the speed you have to load the module with the corresponding option for speed (e.g. for 32k Baudrate). list the actually loaded modules: lsmod unload the i2c-module: rmmod i2c_bcm2708 load the module with the speed-option: … Continued
[Comparison] optocoupler for triacs (with zero-crossing)
pricing from farnell-distributor (1 piece) all optocouplers with built-in zero-crossing (= usable with triacs) company modell I_FT in mA I_TM in mA V_DRM in V price in euro (01/2017) Vishay IL4118 1,3 300 800 4,55 Toshiba TLP3064 3,0 100 … Continued
[Howto] use GPIO from Raspberry Pi
the Linux-Kernel manages the GPIO-system under the path /sys/class/gpio. Use the following commands to manage the pins (e.g. GPIO 17): activate GPIO 17: echo 17 > /sys/class/gpio/export deactivate GPIO 17: echo 17 > /sys/class/gpio/unexport configure GPIO 17 as … Continued