Best practice for system dataset pool?

[pjc]

The general adage is of course to split your system files from your data, but how crucial is that in the case of FreeNAS?

The OS runs from a USB stick, and it seems like the only things that get stored in the system dataset pool are smb4 caches, debugging cores, and optionally logs. So it doesn't seem like the system dataset holds crucial data for bringing up the system. Am I mistaken?

If I am going to put the system dataset pool on its own device, how resilient does that device need to be? Should it be mirrored? Or, again, is it sufficiently non-critical that a single device is OK?

Or does it really not make much difference, since I don't care about having the drives spin down, nor the periodic blips on the disk access reports?

 

[pjc]

Anyone?

Numerous threads have said it's a bad idea to, say, use a USB stick for .system. Does that mean I should look for an SSD particularly optimized for writing, or will any old SSD do?

Again, does it need to be mirrored? At least one person had a bad experience when their single .system drive went offline.

 

[mjws00]

FreeNAS is designed to be an appliance. The default configuration is one pool. So you can safely say it makes no difference that we are writing to the main pool. The developers know how it works, and it is not in the least bit something to be concerned about. The side effect with respect to drive spin down should be addressed with 9.3 and additional persistent storage... but we'll wait and see.

If you want a second pool for .system, go for it, there isn't any downside besides the time and effort, and possible waste of ports. I'd stick it on a spare ssd or a sata dom. USB is a non-starter, imho. You'd need a pretty advanced use case to justify mirroring and breaking this out. Most are better off just running it as designed.

 

[pschatz100]

Why are you asking this question? What is it that you want to do?

The main issue about not using a USB thumbdrive is related to the fact they generally have a very high rate of failure when you do a lot of writes. They're fine for reading, but not for writing. Originally, I installed my jails on a thumbdrive and had to replace the thumbdrive twice in 5 months.