Move to USB

Setup, Configuration and Use Beginners
1

hello

i have openhab install on pi3. and i connected ssd drive to the USB port. and use the option “move to USB” when i remove the SD the pi is not booting. how can i know if its working fro the sd card or the usb?

thanks

2

You need the SD card to boot unless you have setup the RPI to boot from the SSD hard drive.

3

but how can i know if its now booting from sd or ssd ?

4

This is a question for the RPI forum and has nothing to do with OH. Do a search for how to use linux commands to get the info you want.

If you want to boot from the SSD then see this link.
https://www.raspberrypi.org/documentation/hardware/raspberrypi/bootmodes/msd.md

5

why there is nothing to do with openhab ? i use “move to usb” from openhabian-config menu

so now i have openhab on sd and on ssd. so how can i know if openhab working from sd or ssd

6

If using openhabian-config to move to USB then you are booting from the SD card. If you use the link posted above then you can setup the RPI to boot from the SDD and remove the SD card.

I use the RPI and booting from SSD, works well.

Are you wanting to boot from the SSD?

7

i don’t want problem with the sd card. i had few problem when the data was corrupted. and i saw that is recommended to buy ssd for mpr reliability

so if its still boot from the sd card. what “move to usb” are doing ?

8

Reducing the amount of writes to the SD card.

9

so its better to boot directly from the ssd ?

there is an option to go back to sd card boot ?

thanks

10

The raspberryPi always boots from SD card firstly. It can not use USB directly.
The root filesystem is normally also on sd card. when moving to usb, the rasp will boot still from sdcard, but switch then to the root filesystem on the usb ssd drive instead using the
rootfs form sdcard.
All programs will then write/read to/from SSD drive. no data are written to internal sdcard .
This has some advantages:

  • you can install more (more space)
  • you do not care about write cycles as SSD controller will manage writing data to different flash locations to minimize flash cell failures. if the ssd is very big, there is much room to do this and a ssd should work for years.
11

This is a four-year-old thread. I can understand wanting to close the loop, but there have been many similar discussions since then.

I’d usually just leave it alone, but…

This is only true for older RPis. The RPi4 and RPi3 can both boot from USB drives.

The general recommendation with openHABian on an RPi is to use an SD card with the ZRAM feature and a UPS. ZRAM logs to memory and only saves to the SD on a system restart, so card wear is minimized and the risk of power failure while writing data is greatly reduced. The UPS then takes it a step further by preventing power loss altogether. I’ve been doing this for 4+ years and haven’t had a single SD failure.

I’ve got nothing against using SSDs and have thought about using one in the past, but it comes with an added energy cost since the SSD will be constantly running to record logs. So for me, the costs outweigh the benefits. Others may (and definitely do) disagree, which is fine. Everyone should do what’s best for themselves.

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