Single Board Revolution: Preventing Flash Memory Corruption

An SD card is surely not an enterprise grade storage solution, but single board computers also aren’t just toys anymore. You find them in applications far beyond the educational purpose they have emerged from, and the line between non-critical and critical applications keeps getting blurred.

Laundry notification hacks and arcade machines fail without causing harm. But how about electronic access control, or an automatic pet feeder? Would you rely on the data integrity of a plain micro SD card stuffed into a single board computer to keep your pet fed when you’re on vacation and you back in afterward? After all, SD card corruption is a well-discussed topic in the Raspberry Pi community. What can we do to keep our favorite single board computers from failing at random, and is there a better solution to the problem of storage than a stack of SD cards?

Continue reading “Single Board Revolution: Preventing Flash Memory Corruption”

Which SD Card to Use in a Pi?

There is surprising variation in the performance of SD cards. They are not all created equal and the differences can impact the running of your Raspberry Pi, no matter which model. [Jeff Geerling] wondered exactly how different cards would affect system performance. He ran a number of tests on cards ranging from cheap no-names to well-known brand names. The no-name cards fared pretty badly but even among the brand names there is considerable variation.

microsd-cards-all-tested-raspberry-pi

[Matt] over at Raspberry Pi Spy also tested SD cards and found similar differences. Both tested microSD cards. [Jeff’s] tests were solely on the Pi while [Matt’s] were on Windows 7, Ubuntu, and a Pi.

The discussions in the blog about what to measure were as interesting as the actual results. That lead to determining which software tools to use for the measurement. For example, a system doing a lot of small database reads and writes might work better with one SD card while a system storing and then streaming videos might work better with another card. Another interesting result is that the Pi’s data bus greatly limits the access speeds. [Jeff] measured much higher speeds running the same tests using a Mac with a USB dongle. The cards are capable of much more than the Pi can deliver.

[Matt] also checked the capacity of the SD cards. There are a lot of fakes floating around marked with higher capacities than they actually support. Even getting a brand name card may not help since some are counterfeit. So beware: if the price it too good to be true, it very well may be.