Raspberry Pi

Cockbook

My collection of hints, tips and tricks (supporting my memory and maybe also helping others).

Mounting USB drives

• Automount USB-Drives in Raspbian
  • One may use USBmount and autofs
  • I prefer udevil as used by OpenElec to get a /media/<device_label> mounting location
  • I downloaded the 0.4.3/udevil_0.4.3-1_all.deb from https://github.com/IgnorantGuru/udevil/tree/pkg
  • TODO: describe build process + udev rules from open elec

• Slow USB drive performance?
  • Mount with option 'noatime' or 'relatime'
  • Mount without option sync (e.g. keep default async)
  • If using ntfs file system, try mounting with option 'big_writes', see for example http://obihoernchen.net/wordpress/tag/big_writes/

Samba server / NAS

• How to install?
  • Raspberry Pi: Samba Server installieren (German)
  • Low Budget NAS mit einem Raspberry PI (German)

• Slow disc performance?
  • see 'Slow USB drives' above
  • use Raspbian, etc without GUI to get as much CPU power for file-transfer as possible (OpenELEC or RaspBMC constantly result in about 10-20% CPU load when idle, use top to check!)

Misc Q&A

• Q: Why does my Pi restart when hotplugging a USB drive?
  • http://thestuffsido.blogspot.de/2013/05/fixing-raspberry-pi-hotplugging.html
  • http://therandomlab.blogspot.de/2013/01/raspberry-pi-mod-to-avoid-shutdown-on.html

• Q: Does Raspberry support WOL?

A: No: the Ethernet chip is connected via USB (http://www.raspberrypi.org/forum/viewtopic.php?f=53&t=39714)

• Q: The new password is to short, or too simple

A: Try adjusting the PAM settings in /etc/pam.d/common-password:

• remove the 'obscure' setting for pam_unix.so, and add your desired minimum length (e.g. minlen=2)

 password        [success=1 default=ignore]      pam_unix.so sha512 minlen=2

!! This is not recommended if your box is connected to the internet or if it contains private data noone should know!!

But it's nice for testing (if you cannot or do not want to use auto-login.)

• Q: How to configure static IP?

A: In /etc/network/interfaces:

 iface eth0 inet static
   address 192.168.0.31
   netmask 255.255.255.0
   gateway 192.168.0.1

• Q: How to read core temperature, etc?

A: vcgencmd: $vcgencmd measure_temp

• External USB HDD spin down
  • hdparm does not work with my WD Elements (SG_IO: bad host status: 0x7)
  • hd-idle works:

hd-idle -a sda -i 600

for details, see for example http://blog.is-a-geek.org/festplatten-in-den-standby-modus-versetzen-unter-ubuntu-desktopserver-mit-hd-idle (German)

Useful stuff

• wikipedia:Raspcontrol with nginx
  • http://www.foxplex.com/sites/raspcontrol-webinterface-auf-dem-raspberry-pi/ (German), http://www.foxplex.com/sites/performanter-nginx-webserver-auf-dem-raspberry-pi-mit-php-und-apc/ (German)
  • http://menzerath.eu/artikel/raspberry-pi-raspcontrol-installation-funktionen/ (German)

Things I want to (or might) try sometime

• Explore overclocking limits of my RaspBerry - currently I'm using medium set via raspi-config
  

--> Raspberry Pi Stress Tests

• Mathematica on Raspberry Pi, for free

• NAS/Samba

• try adjusting 'socket options' in (/etc/samba/smb.conf) to increase NAS performance: some websites recommend to disable the 'socket options', some recommend to set:

socket options = TCP_NODELAY IPTOS_LOWDELAY SO_RCVBUF=65536 SO_SNDBUF=65536

• adjust memory split - smaller GPU memory for server
• ext4 vs ntfs for storage drive

• Temperature Sensor DS1820
  • http://www.cl.cam.ac.uk/projects/raspberrypi/tutorials/temperature/
  • https://www.raspiprojekt.de/anleitungen/schaltungen/9-1wire-mit-temperatursensor-ds18b20.html?showall=&start=1 (German)
  • http://kopfkino.irosaurus.com/tutorial-ds18s20-temperatur-sensor-an-einem-raspberry-pi/ (German)

• Adjust swap file (size, location -> (ext4) HDD): http://manpages.ubuntu.com/manpages/hardy/man8/dphys-swapfile.8.html

• bfq IO scheduler BFQ to increase throughput

Some links

Project sites

• University of Cambridge / Raspberry Pi Computer Laboratory
• raspiprojek (German)

Blogs, forums, etc

• http://www.raspberrypi.org/phpBB3/
• Stm Labs Forum / Raspbmc
• Wel!s Blog (German)
• Raspberry Pi Blog of Jan Karres (German)

• Raspberry Pi in Wikipedia

Misc

• Out Of Box Software (Recommended)
• R-Pi_Hub

Manuals

• The Debian Administrator's Handbook