RaspberryPi mSATA instead of SD-card

May 2018

I run a RasPi 3 with an openHAB-installation. The whole installation is, as far as possible, configured for seldom write access. Without any log files it is not possible. From time to time something needs to be changed and information is needed to rectify errors. Setup has been done - as by anyone else too - with a SD-card, from which the RasPi boots. After app. 2 years there were unexplicable faults, the RasPi needed to be restarted every few days. This is not an unknown issue, mentioned all over the net. Just set it up again with a new SD-card? No ;-)

SD-cards are not meant for exhaustive write access. They are not the ideal storage media for running an operating system and applications 24/7. Hence I would have needed a new card from time to time and additionally I would have had to invest time to setup everthing again and again. Or take the risk to inherit faulty files when doing a 1:1-copy from a previous card. There is another option: newer RasPis can boot from a drive connected to the USB-port! This means, one can use a "real" drive (magnetic disk or SSD e.g.) or a thumb drive (pls. be aware of the limitations mentioned in the original blog post!).

The original blog post can be found here. All steps needed to create a bootable medium are described.

I decided to use another option: a mSATA "disk".

  • low energy consumption
  • fast (limited by low throughput of the USB port)
  • small
  • not sensitive to shocks (in comparison to a magnetic disc)
  • like a SSD better suited for extensive write operations than a SD-card

3 parts are needed: a mSATA, an USB-to-mSATA-converter and an USB-cable to connect the converter to the RasPi. The mSATA is plugged onto the converter and then fastened by screws. The combination of mSATA and converter is then fastened onto the RasPi with distance rolls provided with the converter (BUT: do this AFTER you have prepared the mSATA with the necessary data!!!). Finally plug in the USB cable and you are finished.

The capacity of the mSATA can be chosen accoring to your needs, the minimal size is the same as for a SD-card. Take a look at the specifications of the converter to avoid incompatibility.

The combination shown here runs for 2 months now without issues (click on the picture to enlarge):

mSATA converter

mSATA disc

A nice side effect: the RasPi is faster than before, as it was limited by write access rather than CPU-capacity.