SD Card containing OS and apps dead after three months use

[Frank Talamy]

Hi everyone,

I've been using the BeagleBone Black for a while now. I got my apps running just fine for like 2-3 months straight, not a single problem.

OS : Debian Wheezy installed on Samsung 4GB µSD card.

Cross compilation platform : ELDK (armv7-hf)

I've tested my apps on different brands of SD Cards (Kingston, samsung, sandisk ...) and have killed several Kingston cards in a matter of days. By killing, I mean the BeagleBone wasn't booting on them anymore and they were no longer mounted when plugged via a USB-Card-reader. I had this kind of dmesg output (the [...] here means a lot of the same 7 lines in a loop):

[626903.528266] sd 11:0:0:0: [sdd] Device not ready
[626903.528268] sd 11:0:0:0: [sdd]  Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
[626903.528272] sd 11:0:0:0: [sdd]  Sense Key : Not Ready [current]
[626903.528275] sd 11:0:0:0: [sdd]  Add. Sense: Medium not present
[626903.528279] sd 11:0:0:0: [sdd] CDB: Read(10): 28 00 00 00 00 00 00 00 08 00
[626903.528287] end_request: I/O error, dev sdd, sector 0
[626903.528290] Buffer I/O error on device sdd, logical block 0
[626903.530266] sd 11:0:0:0: [sdd] Device not ready
[626903.530269] sd 11:0:0:0: [sdd]  Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
[626903.530272] sd 11:0:0:0: [sdd]  Sense Key : Not Ready [current]
[626903.530275] sd 11:0:0:0: [sdd]  Add. Sense: Medium not present
[626903.530279] sd 11:0:0:0: [sdd] CDB: Read(10): 28 00 00 00 00 00 00 00 08 00
[626903.530287] end_request: I/O error, dev sdd, sector 0
[626903.530290] Buffer I/O error on device sdd, logical block 0
[626903.532391] sd 11:0:0:0: [sdd] Device not ready
[626903.532393] sd 11:0:0:0: [sdd]  Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
[626903.532396] sd 11:0:0:0: [sdd]  Sense Key : Not Ready [current]
[626903.532400] sd 11:0:0:0: [sdd]  Add. Sense: Medium not present
[626903.532404] sd 11:0:0:0: [sdd] CDB: Read(10): 28 00 00 00 00 08 00 00 08 00
[626903.532412] end_request: I/O error, dev sdd, sector 8
[...]
[626903.812724] sd 11:0:0:0: [sdd] Device not ready
[626903.812725] sd 11:0:0:0: [sdd]  Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
[626903.812728] sd 11:0:0:0: [sdd]  Sense Key : Not Ready [current]
[626903.812731] sd 11:0:0:0: [sdd]  Add. Sense: Medium not present
[626903.812734] sd 11:0:0:0: [sdd] CDB: Read(10): 28 00 00 00 00 00 00 00 08 00
[626903.812740] end_request: I/O error, dev sdd, sector 0
[626903.814725] sd 11:0:0:0: [sdd] Device not ready
[626903.814728] sd 11:0:0:0: [sdd]  Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
[626903.814731] sd 11:0:0:0: [sdd]  Sense Key : Not Ready [current]
[626903.814735] sd 11:0:0:0: [sdd]  Add. Sense: Medium not present
[626903.814739] sd 11:0:0:0: [sdd] CDB: Read(10): 28 00 00 00 00 00 00 00 08 00
[626903.814747] end_request: I/O error, dev sdd, sector 0
[626903.820536] sdd: detected capacity change from 3947888640 to 0

That's why I chose to use Samsung sd cards instead. Everything was fine for 2-3 whole months, but now I had one of my systems getting the exact same symptoms as when using the Kingston cards.

Did anyone experience this kind of problem using his beagle bone so far ?

Does anyone have an idea of something that could damage the SD card so much which is or isn't directly related to the use of a beagle bone black (Heat, compulsive logging, ...) ?

Can anyone suggest a brand that has solid and enduring SD Cards for an app that is logging quite regularly ?

Thank you for your time,

FT

[Robert Nelson]

I use SanDisk Ultra's 16GB's on my bbw & bbb's on my gcc testing farm.
Those microSD's have been running fine for almost a year now, under
100% load for 24/7 bulding/testing gcc stable branches. (lots of file
deletions/creations). Previously to that i had been running SanDisk
Ultra's 8GB variants, but starting with gcc-4_8-branch i began to run
out of build space.

http://rcn-ee.homeip.net:81/dl/gcc/archive/20140610-11:24-gitb28747e-gcc-4_9-branch-am335x-boneblack-512mb-1/

Regards,

--
Robert Nelson
http://www.rcn-ee.com/

[Brandon I]

With a 16Gb card, you'll most likely get about 2 years use before the card fails, assuming you had 2gb free on your failing cards card, the 16Gb card has the same number of writes until failure for the memory blocks, and the same disk activity.

This assumes that you're have a perfect power supply that never shuts off during a write (which will damage the memory cells) or unflushed operation (which can corrupt the filesystem).

If you're writing to flash media, it will eventually fail. :-\ Ideally, you would have your os disk read only (read only partition doesn't necessarily work due to sd card wear leveling controller not being aware of partitions), and log files logged elsewhere where your software could gracefully handle the eventual failure of the log file flash disk. Have this log file disk easily accessible for customers to change.

You could not flush your log file writes until some sort of failure or buffer size, so that you're not writing whole erase blocks for a sentence worth of log message. And, of course, turn off all the access time capabilities with your mount options (noatime, nodiratime). 

The only solution is to reduce the number of writes each memory block is seeing in a day, and be aware that eventual failure can't be avoided if writing anything.

[Frank Talamy]

Thank you guys for your lightning quick response !! I won't have the chance to try anything until next week, but I'll definetly give you some feedback about my new µSD card experiences. Your answers look promising :)ff

[Fred Basset]

Brandon,

I'm curious as to how you calculated a lifetime of 2 yrs for the 16Gb card with 2Gb free?

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[Brandon I]

I assumed that everything is the same (flash technology, memory block size, memory block life, etc) between the 4Gb and 16Gb card, except the number of memory blocks. The more free memory blocks there are, the more blocks the wear leveler can touch before cycling through all of them.

I assumed you had 2Gb of free space on your old card, so, scaling the time by the extra memory blocks available: 3months * 14Gb/2Gb = 21 months.

Flash is crazy dense and cheap to make, but the eventual failure is the price you pay for, literally, shooting electrons through glass. :)

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