I'm planning a project that will read data from an I/O board. The micro SD card would hold data for input bit identity, labeling ?, then logging after events end.

Nothing would be written to or read from the micro sd, unless an event takes place, usually 2-10 events/hour. System will run 24/7 for years, hopefully. Is a micro sd card the best way? Is it reliable enough?

2 Answers 2


We've been maintaining a network of loggers (60+ currently deployed) using SD card connected directly to the SPI pins (see: http://www.mdpi.com/1424-8220/18/2/530 for details) and our experience is that the SD cards are really reliable provided you don't have a brown-out when they are writing, even when we abuse them with hot surface deployments in the tropical sun. And we buy them used, (since the older, smaller Nokia & Sandisk cards have lower sleep currents) but test them well with H2testw. However there is one problem that develops over time: the actual SD adapters are not made that well, and tend to have solder flux residue left on the little pads used to hold the contact springs, and these will corrode over time if moisture gets in. I give everything a sonic bath in 90% isopropyl until the parts are squeaky clean, and then always put 2x10gram desiccant packs into the logger housings (with color indicator beads). If you are careful about the cleaning, the contacts last for years, but if you forget, and moisture gets into the housing, then the SD card contact spring solder points are often the first things to corrode.


As far as durability concern, SD cards are quite durable.

8-10 years data storage and operations would be OKAY. In a practical scenario, average time is about to 5-6 years.

Just you have to keep some important and necessary instructions/cautions keep in mind while dealing with SD card and for its long life.

Importantly, use standard standard manufacture SD card (suggestion - Swissbit)

  • Don't store them below -40 °C or above +70 °C
  • Don't pressurized

Here are a few links, which may help you.


SD cards generally have wear leveling (https://en.wikipedia.org/wiki/Wear_leveling)

Hope, this will helpful.

  • My concern wasn't so much the age, but read/write frequency and quantity. And the mean time between failure. I've read a bit in years past that lots of long-term read/writes are not the best use of SD/Micro SD cards. I'm hoping the technology has improved.
    – Ashton
    Dec 19, 2017 at 17:33

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