once I had sd card corrupted, so I couldn't use it again for raspberry. Tried everything.

Now different error. I disabled swap on sd card and placed my script files and some files on ram memory to save sd card from corruption again. Every day made backup from ram memory to sd card. This time raspberry pi up time was about two weeks. And I found out that raspberry pi gives this error. When I try to write something it gives me "Read-only file system" even when i typed reboot it showed me this error. I unplugged the power of raspberry and tried to start it again. No luck. Same what I had with first card. Both times I'm using Thosiba SDHC class4 4GM. What caused this error? I placed my files in location /dev/shm/ - found that it's ram memory and I can keep small files there. I was using about 15MB of that memory only. I have two raspberry pi more with same clone img but different sd cards. SD cards on those raspberry's are original NOOBS sd card, witch came with raspberry pi.

What should I do to avoid from this error again. What caused this error? Do I need to worry also about those two raspberry ?

If it's helpful I'm using these raspberry's to measure temperature and register door opening in server room. Using DS18b20 sensor and for doors there are some leds attached to gpio. If need something else to discover problem, please ask. Searched all network, didn't fine fix for this.

2 Answers 2


Please, tell us your exact SD card model. Anyway, if you ask me, I would recommend using high-speed SD cards, i.e. class 10 would be ok, considering you barely save any money if you use low-speed card. You can check performance of different cards here: http://elinux.org/RPi_SD_cards

Btw, how many I/O operations do you make to you card? 2 weeks seems a little bit to low for reasonable temperature logging (once every second?) regarding flash memory corruption.

Do you have any other "suspicious" conditions, e.g. high temperature in the room, RF, EMI noise, to high humidity etc.?

Also, whatever you do, always try to gracefully logout from console before plugging the power out of your raspberry; this how, you won't get any in-the-middle-of-operation interruptions.

You can also check your dmesg.

  • To avoid from that there is so much writing I changed temperature measuring to 1min. Every min it access device and reads temperature. Also I have script for writing that temperature measurement in rrd file every 1min and also a script that draws graphic from rrd tool. every 5min and one more thin I have is door switch. Every time the circuit is interrupted (opened or closed) it writes date and time when it happened. And I store that all in /dev/shm/ Also I have apache.
    – iamjansons
    Oct 17, 2013 at 7:04
  • Why not store everything on a thumbdrive ? I have had a San disk ultra fail on me and it won't copy raspian... The pi Is also picky about SD cards.. Make sure its firmly in place '
    – jason
    Oct 23, 2013 at 9:53

This answer may help you. (See link) It is because the SD card is mounted in read-only mode when you insert it into the Pi. I would insert back into the PC and either unmount and remount it as rw or edit the /etc/fstab


  • Also if you haven't done it already, check the physical switch on the side of the SD card hasn't slipped into the read-only position (if it has one).
    – p1l0t
    Oct 16, 2013 at 17:53
  • I think that's the first thing that everyone checks. But thanks for answer. I cloned img to raspberry NOOBS card and see if it will work. I will update about news. But anyway I have still two raspberries witch runs with NOOBS card and they were installed at the same time as this one with toshiba card. Hope that's the problem. Thanks again.
    – iamjansons
    Oct 17, 2013 at 7:10

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