zfs: the exponential file system from hell

[Attila Nagy]

On 09/27/2013 03:52 PM, Ronald Klop wrote:
>
> So, if I understand you correctly, you compare the output of free 
> space of zpool list (of the whole pool) to the output of df of one of 
> size zfs's.
Yes.
> So the conclusion is that zpool list shows you how much space there is 
> in the pool and df shows the 
> amount-of-space-of-one-zfs-if-you-don't-do-change-other-zfs's-in-the-pool-in-the-meantime.
Almost, it wasn't about the free space, but the capacity.
> But I understand it is a bit confusing if you come from traditional 
> fixed-size filesystems.
Yes, for machines, which rely on df's output. :)
That's what happened here, and that's where an otherwise linear fill up 
went exponential.
I've been asked about it, and graphed it, because it looked funny.

> You can emulate a fixed-size filesystem by using quota's. Give all 
> zfs's 1/6 of the space in quota and your df will work perfectly.
Agreed, that's the easiest way to fix this.