Changes in vfs.zfs.arc_max on 13

[Pete Wright]

On 5/11/21 11:40 PM, Andriy Gapon wrote:
> On 11/05/2021 20:09, Pete Wright via freebsd-fs wrote:
>> The next issue I am seeing is that when setting this variable the 
>> example from the handbook states you can do something similar to this 
>> (section 20.6.2.3):
>>
>> vfs.zfs.arc_max="40M"
>>
>> This throws an error on my system:
>> $ sudo sysctl vfs.zfs.arc_max=2048M
>> sysctl: invalid unsigned long '2048M'
>> $ sudo sysctl vfs.zfs.arc_max=2G
>> sysctl: invalid unsigned long '2G'
>>
>> Using the human unfriendly form works though:
>> $ sudo sysctl vfs.zfs.arc.max="2000000000"
>> vfs.zfs.arc.max: 0 -> 2000000000
>> $
>>
>> Is this a bug, or would it be best to also update the documentation 
>> accordingly to reflect this?  Personally I like the old behavior as 
>> it's easier on my eyes.
>
> Are you sure that that is a recipe for sysctl?
> It looks like it was for loader.conf.
>

Ah interesting, the examples certainly refer to loader.conf knobs. I had 
mistakenly assumed that the sysctl values would take the same form.  
Section 20.6.1 of the handbook isn't clear on this distinction:
"This value can be adjusted at runtime with sysctl(8) 
<https://www.freebsd.org/cgi/man.cgi?query=sysctl&sektion=8&format=html> 
and can be set in /boot/loader.conf or /etc/sysctl.conf."

zfs-module-parameters(5) is a bit more clear on this it looks like. Is 
it common for loader variables to accept different formatted values for 
the same knob?

-pete

-- 
Pete Wright
pete at nomadlogic.org
@nomadlogicLA