Raspberry PI: freeze durante il download dati

Uso il Raspberry Pi durante la notte per eseguire il backup dati di alcuni siti sparsi su internet facendone il download dei dati.

Mi è capitati diverse volte che il Rasp-Pi vada in freeze e non risponda via rete. I log che trovo in /var/log/kern.log sono questi:

Apr 28 16:29:39 raspberrypi kernel: [85223.191749] net_ratelimit: 3722 callbacks suppressed
Apr 28 16:29:39 raspberrypi kernel: [85223.191790] smsc95xx 1-1.1:1.0: eth0: kevent 2 may have been dropped
Apr 28 16:29:39 raspberrypi kernel: [85223.191882] smsc95xx 1-1.1:1.0: eth0: kevent 2 may have been dropped
Apr 28 16:29:39 raspberrypi kernel: [85223.191961] smsc95xx 1-1.1:1.0: eth0: kevent 2 may have been dropped
Apr 28 16:29:39 raspberrypi kernel: [85223.192025] smsc95xx 1-1.1:1.0: eth0: kevent 2 may have been dropped

Googolando ho trovato questa possibile soluzione su http://www.raspberrypi.org/phpBB3/viewtopic.php?p=134136:

I performed the following suggested modifications mentioned in this thread.

• Updated the firmware according to this blog post: http://www.stuffaboutcode.com/2012/07/raspberry-pi-kernal-panic-solved-by.html i.e. (add “sudo” before each command if you’re not logged in as root) 

  apt-get install git-core
wget http://goo.gl/1BOfJ -O /usr/bin/rpi-update && chmod +x /usr/bin/rpi-update
apt-get install ca-certificates
rpi-update

• Increased “vm.min_free_kbytes” to 16384 in /etc/sysctl.conf:

  nano /etc/sysctl.conf

  Replace the number 8192 after “vm.min_free_kbytes =” with 16384, i.e. double it.

• Added “smsc95xx.turbo_mode=N” to /boot/cmdline.txt:

  nano /boot/cmdline.txt

  Paste “smsc95xx.turbo_mode=N” after all other entries in the file.

• After that I pulled the plug, let the RPi rest for a few seconds before plugging it in again. Done!