1

I've read (here: Is the Raspberry Pi suitable for running continuously, 24/7?) that using a Raspberry Pi 24/7 is possible as long as you don't write too much on the SD card. So, how do you know if your system/application writes on it ? Are there kind of log of this ?

To be more precise, in my case I'm using the Raspberry as a DSP and I guess I'm not writing anything on it but, how to be sure ?

  • Yo, dude, I heard you like logs! So, I wrote logs about writing your logs!! – Jacobm001 Jan 22 '16 at 23:23
  • Haha ! I got it. I'm french ;) We love plural wordS. – Corentoulf Jan 22 '16 at 23:26
2

Assuming you are no longer talking about logs in particular.

Have a look at /proc/diskstats. If you cat /proc/diskstats you will see statistics for various devices.

Each device has 11 entries as follows.

Name            units         description
----            -----         -----------
read I/Os       requests      number of read I/Os processed
read merges     requests      number of read I/Os merged with in-queue I/O
read sectors    sectors       number of sectors read
read ticks      milliseconds  total wait time for read requests
write I/Os      requests      number of write I/Os processed
write merges    requests      number of write I/Os merged with in-queue I/O
write sectors   sectors       number of sectors written
write ticks     milliseconds  total wait time for write requests
in_flight       requests      number of I/Os currently in flight
io_ticks        milliseconds  total time this block device has been active
time_in_queue   milliseconds  total wait time for all requests

See https://www.kernel.org/doc/Documentation/block/stat.txt for further detail.

  • That is what I was looking for. – Corentoulf Jan 25 '16 at 10:59
1

Yes there are logs, most should be under /var/log.

Use the command ls /var/log -lrt to get a reverse time ordered list of files in that directory.

You can tune some logging with the file /etc/rsyslog.conf. If you want to disable as much logging as possible add a line with *.* ~ just after the #### RULES #### comment block.

Not all logging may be controlled in this fashion. Some programs bypass this configuration file and have their own configuration file for logging.

  • Thanks! So, you mean I can disable log to prevent a few writes. But is there a way to control if the app I'm running is writing things on the SD card to work ? – Corentoulf Jan 22 '16 at 23:29
  • If you run an app which writes to a file wouldn't you want that output? If you don't want the output perhaps get the app to write to a file on a RAM disc. That won't impose any wear on the SD card. – joan Jan 22 '16 at 23:37
  • Relevant: unix.stackexchange.com/a/84905/25985 – goldilocks Jan 23 '16 at 2:41
  • I don't know if the app is writing on the SD card. I'm looking for a way to detect if the app writes things on the SD card.Managing log's writes is another point. – Corentoulf Jan 24 '16 at 23:19
0

You could use my Nard SDK as a platform base. It doesn't use the SD card at all after bootup. One can even remove the SD card and the system will continue to operate just fine.
http://www.arbetsmyra.dyndns.org/nard

  • This looks really interesting... Will I be able to run any Raspbian binary within the Raspbian emulator or is it limited ? – Corentoulf Jan 24 '16 at 23:16
  • All console based Raspbian Wheezy binaries should work. Avoid applications depending on a GUI and X-Windows though. There is a list at the website with tested examples applications. – Ronny Nilsson Jan 25 '16 at 10:40
  • Okay, I'll may give it a try so. – Corentoulf Jan 25 '16 at 11:00
0

If you are looking for Raspbian that can be read only on demand, there is a special blackout-proof flavor of Raspbian called IPE – Industrial Perennial Environment R1. http://nutcom.hu/ipe-r1

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.