how Important is the system dataset

[luk]

I looked around in the forums and found out that the constant writing my hdd's do are due to it writing to .system dataset. I only had 1 pool so didn't think I would be able to change the location, but to my surprise there was an option to add it to the boot device, so I did (finally I can make use of that 250gb). Now I'm wondering if my boot drive where to fail, will data on my pool also be lost, e.g. raid configurations? Based on "https://www.truenas.com/docs/core/system/systemdataset/" it doesn't look like it, but I wanted to be sure. My reason for doing this is for drive longevity/noise. I saw a moderator mentioning "mechanical drives don't wear out from writing", and if that is the case I would be happy with not hearing the the drives write on and off. I don't spin my drives down, so doing this wouldn't affect the load cycle counts I suppose? Thanks for reading!

 

[sretalla]

I'm wondering if my boot drive where to fail, will data on my pool also be lost, e.g. raid configurations?

No.

there was an option to add it to the boot device, so I did (finally I can make use of that 250gb).

For an SSD boot pool that's a perfectly acceptable option... USB stick boot pools, not so much.

What you're doing is fine.

 

[anodos]

Off the top of my head, the system dataset contains Active Directory secrets if you're joined to AD. Winbindd will update the shared secret for the AD machine account every 14 days by default. There is risk that you could potentially end up with an edge case where the boot device fails and your last config backup has an out of date password, which would basically take your NAS out of production until you can obtain domain admin creds to rejoin AD.

For home users, replacing a failed boot device will be more annoying than anything related to the system dataset. My only real guidance related to boot devices is to avoid USB for it.