Creating multiple datasets under volumes

[Rusky]

I often see someone creating a volume, let's say Media, and it shows up as

Media
|
>Media

Then they'll create another dataset under it so it shows up as

Media
|
>Media
|
>Media

Is there a reason for this? Is there any issues with just using the first dataset that gets created? Am I missing something?

 

[Nick2253]

First thing, be mindful of the terminology you are using. "Volume" in ZFS means something very different than what I think you mean.

Top level structure in ZFS is a pool. By default (and I'm not sure if it's because it's required, or if it's just a FreeNAS thing), FreeNAS creates a top-level dataset that has the same name as the pool. Then, under that top-level dataset, you create additional datasets. Sharing that top-level dataset directly is not a supported configuration. For example, on my ZFS, my tree looks like:

Code:

NickVol01
		|
		>NickVol01
				 |
				 >Videos
				 >Media
				 >Pictures
				 etc.

 

[Rusky]

First thing, be mindful of the terminology you are using. "Volume" in ZFS means something very different than what I think you mean.

Top level structure in ZFS is a pool. By default (and I'm not sure if it's because it's required, or if it's just a FreeNAS thing), FreeNAS creates a top-level dataset that has the same name as the pool. Then, under that top-level dataset, you create additional datasets. Sharing that top-level dataset directly is not a supported configuration. For example, on my ZFS, my tree looks like:

Code:

NickVol01
		|
		>NickVol01
				 |
				 >Videos
				 >Media
				 >Pictures
				 etc.

I do recall reading that a volume isn't a volume but the GUI displays it as Volume Manager so it always throws me off.

Your explanation has made the most sense out of everything I've read so thank you very much

 

[danb35]

By default (and I'm not sure if it's because it's required, or if it's just a FreeNAS thing), FreeNAS creates a top-level dataset that has the same name as the pool.

It's a ZFS thing, not just a FreeNAS thing.

"Volume" in ZFS means something very different than what I think you mean.

OTOH, FreeNAS calls the pool a volume, so...

Is there any issues with just using the first dataset that gets created?

The first dataset is the root of the pool. You don't generally want to share that. You definitely don't want to share it if you're going to run jails, virtual machines, or do anything other than share files that live on that pool.

 

[Nick2253]

OTOH, FreeNAS calls the pool a volume, so...

You know, I guess I had never paid that much attention to the names in the GUI, because sure enough...

 

[Ericloewe]

FWIW, the "volume" designation is finally being retired. About three years too late:

https://redmine.ixsystems.com/issues/26111

Please join me in opening a bottle of champagne once that piece of confusion-inducing terminology is gone for good.

 

[Nick2253]

Please join me in opening a bottle of champagne once that piece of confusion-inducing terminology is gone for good.

w00t! It's about freaking time!