I have a JBOD array consisting of two external USB drives, and have a third one on standby that I plan to add to the array once the second drive starts filling up. I am however a bit curious about the inner workings of JBOD on macOS.
When I created the array and started moving data to it, I was able to see that only the first drive showed activity (LED blinking and could hear the drive spinning). It wasn't until it reached about 8 TB of data that the second drive spun up and began working. This was expected.
I understand that JBOD will start filling up drives on demand and not spread data everywhere, but what happens if I delete a whole bunch of data that was stored in the first drive and the second one is already being used? Will new data be written to the first drive or macOS will start moving previous data from disk2s3 to disk2s2?
I would like to be able to see how much data is being used on each drive, or perhaps see which files are stored on each one. This is strictly curiosity. I'm also a bit worried about adding the third drive and lose data somehow (although I'm sure I won't).
Some screenshots for context:
When I created the array and started moving data to it, I was able to see that only the first drive showed activity (LED blinking and could hear the drive spinning). It wasn't until it reached about 8 TB of data that the second drive spun up and began working. This was expected.
I understand that JBOD will start filling up drives on demand and not spread data everywhere, but what happens if I delete a whole bunch of data that was stored in the first drive and the second one is already being used? Will new data be written to the first drive or macOS will start moving previous data from disk2s3 to disk2s2?
I would like to be able to see how much data is being used on each drive, or perhaps see which files are stored on each one. This is strictly curiosity. I'm also a bit worried about adding the third drive and lose data somehow (although I'm sure I won't).
Some screenshots for context: