Does FreeNAS need an operating system drive

[TimGeerts]

I'm building a new server at the moment, and was planning on just running freeNAS from a 16GB USB stick. I've got 4x2TB as storage drives, which I will configure as two vdevs of 2x2TB mirrors.

I was wondering, how does freeNAS actually work internally when I create jails and what not for different applications (say, Plex, Sonarr, or a virtualbox with openFLIXR on it)? Does it create those jails on the storage drives that I'm including, or is it better to add an SSD to the build, and have freeNAS create the "software" part on that drive?
If so, do I need to install freeNAS on that drive in stead of the USB stick? Or can I point to that drive when creating a virtualbox jail so that it runs on that drive?

Actually, the main question I have is just how FreeNAS works with the different jails added to it. Does it create those on the drive where FreeNAS is installed on, or does it use the storage VDEVS defined for the NAS? My guess is that it's better to have an extra drive in it, but, I'm just not sure how FreeNAS works internally.
The OpenFLIXR i'm referencing is actually a virtual OS that can run in a virtualbox jail, but since that one needs quite a bit of space, I'm thinking of installing FreeNAS on a bigger drive rather then on a 16GB flash drive.

I'm sorry if these seem like dumb questions, but, it's the first time that I'll be working with freeNAS...

 

[danb35]

You can configure where jails are stored in the web GUI, but by default they're on your storage pool. I don't believe it's possible to put them on the boot device, and that certainly isn't the default.

 

[TimGeerts]

Thanks!
So, in the case of my setup (boot from 16GB flash drive, with FreeNAS on), and 2 vdevs of 2x2TB in mirror, my jails (plugins, virtualbox, etc...) will be stored on the mirror drives?
Which would mean that I won't need another, seperate, drive inside my server just to serve as the "software" drive?

 

[nojohnny101]

Correct.

 

[depasseg]

Think of plugins as preconfigured jails. And Jails can be configured to be stored wherever (except on the boot pool) you want. So you can put them in a dataset on your main pool, or you could put them on a separate pool (like an SSD).
http://doc.freenas.org/9.10/freenas_jails.html#jails-configuration

 

[TimGeerts]

Yet, is it beneficial to have a separate drive for your jails? Or doesn't it matter at all?

 

[Spearfoot]

Yet, is it beneficial to have a separate drive for your jails? Or doesn't it matter at all?

@TimGeerts, I don't use jails myself, but I've noticed that many jail users put them on SSD-based datasets to get higher performance. But you don't have to do this; you can just install them to the default location.

 

[Nick2253]

Yet, is it beneficial to have a separate drive for your jails? Or doesn't it matter at all?

In a typical home setting, you probably won't have problems with your jails living on your main pool. If you have a bunch of jails, or you have jails that do a ton of I/O (e.g. high-use databases), then an SSD might make sense. With striped mirrors, I think you'll have plenty of speed and I/O with your main pool.

 

[TimGeerts]

Thanks for the information guys (and girls, who knows)!
I ended up buying a seperate SSD after all, mainly because I have no intention of upgrading my new server anytime soon (bar some storage expansions of course). And, it just gives me a bit more room to play around with.

 

[Nick2253]

Don't forget that if you want the self-healing features of ZFS, you need some kind of redundancy (mirrors, RAIDZx). If you just have one drive in a vdev, then ZFS can tell you if your data goes bad, but it won't be able to fix it.

 

[TimGeerts]

Don't forget that if you want the self-healing features of ZFS, you need some kind of redundancy (mirrors, RAIDZx). If you just have one drive in a vdev, then ZFS can tell you if your data goes bad, but it won't be able to fix it.

Is this statement also true for the "jails" disk (which is what I'd use my SSD for)?
Cause my storage disks will all be mirrored, the jails, if I would choose to put them on a pool consisting of my 1 SSD, won't be mirrored.
But, I don't really see that much problems with it though, my data will still be safe, and maybe I could backup my SSD once in a while to my storage, so I would have my installs and configs backed up?

 

[Nick2253]

Is this statement also true for the "jails" disk (which is what I'd use my SSD for)?

It's true for all ZFS vdevs.

Cause my storage disks will all be mirrored, the jails, if I would choose to put them on a pool consisting of my 1 SSD, won't be mirrored.
But, I don't really see that much problems with it though, my data will still be safe, and maybe I could backup my SSD once in a while to my storage, so I would have my installs and configs backed up?

If your storage disks are mirrored, then they would be fine. It's important, though, to make sure your HDDs and SSD are in separate pools (not saying you were or weren't planning this, just making sure). You could definitely do a backup from your jail pool to your data pool. The easiest way to do that is probably to use ZFS replication.

 

[depasseg]

By default, if you have a vdev with a single disk, then ZFS will detect any file corruption, but will be unable to fix it unless you set copies=2, but that would only give you half the space on your disk and obviously wouldn't survive a failure of that only disk.

 

[Nick2253]

...unless you set copies=2...

TIL. I didn't even know that was an option, and I actually have some use for this. Thanks!