Understanding the System Dataset Pool and it's Default Placement?

[theprez]

Evening -

I just installed FreeNAS SCALE recently - and am impressed. Still getting the hang of things and didn't run into this before - probably because the server I was using didn't have encryption. This install does.

It appears I cannot use a passphrase because the system defaulted to placing the system dataset into the default pool. I'm trying to understand the following:

1) What exactly is the system dataset pool?
2) Was it placed onto the physical drives because I booted off a SD card and it was trying to conserve premature USB/SD Card wear? - I know that's not preferred to use USB/SD Cards, but have it mirrored and am not concerned.
3) Looks like I can go to System Settings -> Advanced -> Configure and point it back to the boot-pool, any advantage in doing that other than it allowing me to use a passphrase instead of a key? Or does keeping it as is help reduce writes to the SD card?

Said differently, it appears the system will automatically decrypt the drives and not prompt for a key or passphrase with this default configuration. If I can prompt to supply a key or enter a key with it like this (instead of a pass phrase) that works also but can't seem to find an option for that.

Thanks

 

[sretalla]

What exactly is the system dataset pool?

Mostly the reporting and logging data used by the system. It's mounted in various paths under /var/db/system

Was it placed onto the physical drives because I booted off a SD card and it was trying to conserve premature USB/SD Card wear? - I know that's not preferred to use USB/SD Cards, but have it mirrored and am not concerned.

It's likely it was for exactly that purpose as USB boot pools were the norm many versions back when this was introduced... I guess it may be time for a revision of that, but for now, it seems it's good for you.

Looks like I can go to System Settings -> Advanced -> Configure and point it back to the boot-pool, any advantage in doing that other than it allowing me to use a passphrase instead of a key? Or does keeping it as is help reduce writes to the SD card?

You can do what you want, but know that you'll quickly burn out an SD card with the system dataset on it... although even without it, you're headed for trouble as you already state you're aware/not concerned.

If I can prompt to supply a key or enter a key with it like this (instead of a pass phrase) that works also but can't seem to find an option for that.

Perhaps check this thread out:

SOLVED - ZFS Encryption USB auto unlock and mount with pass-phrase as I do with GLI.

For years I've automatically unlocked on boot and mounted my encrypted geli disks using remotely mounted USB drives as the geli example script below, so If you steel the box without the remote USB's it's useless. So now I need to do the same with the new ZFS encryption since GLI is no longer...

www.truenas.com

 

[theprez]

Mostly the reporting and logging data used by the system. It's mounted in various paths under /var/db/system


It's likely it was for exactly that purpose as USB boot pools were the norm many versions back when this was introduced... I guess it may be time for a revision of that, but for now, it seems it's good for you.


You can do what you want, but know that you'll quickly burn out an SD card with the system dataset on it... although even without it, you're headed for trouble as you already state you're aware/not concerned.


Perhaps check this thread out:

SOLVED - ZFS Encryption USB auto unlock and mount with pass-phrase as I do with GLI.

For years I've automatically unlocked on boot and mounted my encrypted geli disks using remotely mounted USB drives as the geli example script below, so If you steel the box without the remote USB's it's useless. So now I need to do the same with the new ZFS encryption since GLI is no longer...

www.truenas.com

Thanks for the detailed reply and link.

I moved the system dataset to the boot-device (SD Card) and observed the reporting for that particular disk - looks like about every 5 minutes or so something is written. So, now knowing that level of activity I'm now no longer ok with having the SD card in use as it's much higher than I was expecting.

I've purchased two SSD cards and plan to mirror those - I assume the easiest thing to do now is to Export/Disconnect my pool, reinstall TrueNAS SCALE to the SSD and then reimport my pool?

Thanks

 

[sretalla]

I assume the easiest thing to do now is to Export/Disconnect my pool, reinstall TrueNAS SCALE to the SSD and then reimport my pool?

You could export your config, then reinstall and import the config... that would be easier.

looks like about every 5 minutes or so something is written

I actually think it's every 5-10 seconds, but I guess that doesn't change your mind anyway.

 

[ScaleyNas]

You could export your config, then reinstall and import the config... that would be easier.


I actually think it's every 5-10 seconds, but I guess that doesn't change your mind anyway.

Do you feel moving the system dataset pool to a boot SSD is bad for a SOHO/HOME system? Premature wear of the SSD? Personally, I have no bias as to where it is located, as long as it is a best practice. Thanks.

 

[sretalla]

Do you feel moving the system dataset pool to a boot SSD is bad for a SOHO/HOME system? Premature wear of the SSD?

The amount of data written shouldn't factor into a TBW calculation for an SSD. If you leave it on a pool with HDDs, be prepared to see activity lights and maybe hear writing every 5-10 seconds (this is what most people are complaining about on the forums and want to stop).

 

[ScaleyNas]

The amount of data written shouldn't factor into a TBW calculation for an SSD. If you leave it on a pool with HDDs, be prepared to see activity lights and maybe hear writing every 5-10 seconds (this is what most people are complaining about on the forums and want to stop).

Gotcha. I didn't know that but accidentally realized that my NAS was suddenly more quiet. Which is REEEEEEEEEALLY nice because it sits less than 6 feet from me in my office. LOL I moved it to SSD bc I wanted to switch my encryption from KEY to PASSPHRASE.