Space Not Adding Up

[Clinderw]

Hello,

Can anyone help explain this? I am expecting to have ~17 TiB of usable space but i only have 15.5 - anyone able to explain where the other 1.5 TiB went?

I have 2 RaidZ2 vdevs making up the pool.

 

[danb35]

You specified a single RAIDZ2 vdev in the web calculator, but you have two. That will account for a bit of a discrepancy.

 

[Bidule0hm]

In fact you're supposed to have 21.8 TiB minus the overheads (17.2 is after the 80 % rule which is not accounted for in the GUI numbers) so you probably have some snapshots lowering your available space. Did you enable them?

 

[gpsguy]

Did you remember to preformat the drives with the /xtratracks command?

Just kidding ... FreeNAS has some overhead, there's nothing you can do about it. Trust us, the numbers are correct.

 

[Clinderw]

haha thanks for the quick replys. I trust the numbers are correct - just trying to understand what i'm losing space to and if it minimizable. It seems like a lot is falling out...

I haven't set up ongoing snapshots yet, i have 7GB of manually created ones. This is on my short list of things to set up.

Chris

 

[danb35]

If, as you say, you have two vdevs, each consisting of five disks in RAIDZ2 configuration, the net capacity of your pool will be about 6x that of a single disk, or 18 TB, or about 16 TiB. The remaining difference would be OS overhead and reserved space.

 

[Clinderw]

Its a 6 drive vdev and a 4 drive vdev. If your saying there is ~2tb of overhead, any idea what the system is doing with all that space? Even if its not controllable, it's be nice to be a little more educated. Not trying to be thick or difficult.

Thanks

 

[danb35]

There isn't 2 TB overhead, there's about 500 GB overhead.

 

[Bidule0hm]

Ah ok, two vdevs. Then it's normal, you just have 2x 2 drives for parity instead of only 2 drives with a one vdev pool so you actually have 4 + 2 drives for the data so 6x 3TB which is about 16.4 TiB so you have a bit less than 1 TB of overhead. Everything looks good ;)

 

[Clinderw]

Thanks! I guess my calculations were a little off.

Might switch to just one vdev down the road...i think i might be a little overkill at the moment.

Thanks