Re: Setting sysctl vfs.zfs.arc_max failed: 22

OK, I follow you now.
Thanks for the explanation.
I will try that later tonight or tomorrow.

On Tue, Jul 5, 2016 at 9:45 PM, Allan Jude <allanjude_at_freebsd.org> wrote:

> On 2016-07-05 21:32, Nathan Bosley wrote:
> > I think in about 4 - 5 hours I can show what values I'm using in
> > loader.conf under, say, r302264 and r302265 for comparison. I'm not 100%
> > sure that the problem arose for me in r302265; I merely suspect it.
> >
> > On Tue, Jul 5, 2016 at 9:25 PM, Allan Jude <allanjude_at_freebsd.org
> > <mailto:allanjude_at_freebsd.org>> wrote:
> >
> >     On 2016-07-05 20:27, Steven Hartland wrote:
> >     > Ahh right, let me check that.
> >     >
> >     > On 06/07/2016 00:51, Nathan Bosley wrote:
> >     >> I actually have this same problem.
> >     >> I'll send more details when I get home later.
> >     >>
> >     >> I think the problem started for me after r302265.
> >     >> Before that, I can set vfs.zfs.arc_max and vfs.zfs.arc_min in
> >     >> loader.conf.
> >     >> After r302265, setting either vfs.zfs.arc_max or vfs.zfs.arc_min
> in
> >     >> loader.conf results in the EINVAL errors in 'dmesg':
> >     >>
> >     >> Setting sysctl vfs.zfs.arc_max failed: 22
> >     >> Setting sysctl vfs.zfs.arc_min failed: 22
> >     >>
> >     >> But setting vfs.zfs.arc_meta_limit in loader.conf works fine.
> >     >>
> >     >> But I did notice that using 'sysct' or sysctl.conf for
> vfs.zfs.arc_max
> >     >> and vfs.zfs.arc_min works.
> >     >> I only have problems with setting them now in loader.conf.
> >     >>
> >     >> Like I said, I'll try to send output from my setup later.
> >     >>
> >     >> Thanks.
> >     >>
> >     >> On Tue, Jul 5, 2016 at 6:10 PM, Steven Hartland
> >     >> <steven_at_multiplay.co.uk <mailto:steven_at_multiplay.co.uk>
> >     <mailto:steven_at_multiplay.co.uk <mailto:steven_at_multiplay.co.uk>>>
> wrote:
> >     >>
> >     >>     What is it currently?
> >     >>
> >     >>     Just had a quick play here:
> >     >>     sysctl vfs.zfs.arc_max
> >     >>     vfs.zfs.arc_max: 32283127808
> >     >>     sysctl vfs.zfs.arc_max=32283127807
> >     >>     vfs.zfs.arc_max: 32283127808 -> 32283127807
> >     >>     sysctl vfs.zfs.arc_max=32283127808
> >     >>     vfs.zfs.arc_max: 32283127807 -> 32283127808
> >     >>
> >     >>     Error 22 = EINVAL so I suspect you're requesting a value
> >     which one
> >     >>     of the following:
> >     >>     * < arc_abs_min
> >     >>     * > kmem_size
> >     >>     * < arc_c_min
> >     >>     * < zfs_arc_meta_limit
> >     >>
> >     >>         Regards
> >     >>         Steve
> >     >>
> >     >>     On 05/07/2016 22:56, Eric van Gyzen wrote:
> >     >>
> >     >>         Steven and -current:
> >     >>
> >     >>         I just updated to r302350 with a GENERIC kernel config.
> >     I see
> >     >>         this in
> >     >>         dmesg:
> >     >>
> >     >>              VT(efifb): resolution 1024x768
> >     >>              Setting sysctl vfs.zfs.arc_max failed: 22
> >     >>              CPU: Intel(R) Xeon(R) CPU E5-1650 v3 _at_ 3.50GHz
> >     >>         (3491.98-MHz K8-class
> >     >>              CPU)
> >     >>
> >     >>         The relevant parts of /boot/loader.conf are:
> >     >>
> >     >>              zfs_load="YES"
> >     >>              vfs.zfs.arc_max="6442450944"
> >     >>
> >     >>         Let me know what other information you need.
> >     >>
> >     >>         Cheers,
> >     >>
> >     >>         Eric
> >     >>
> >     >>
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> >
> >     I think the issue might be that the default value of arc_min is
> higher
> >     than when the user is trying to set arc_max to. In that case we might
> >     want sysctl to lower arc_min instead of giving an error?
> >
> >     It would definitely be a POLA violation to have to set arc_min lower
> to
> >     be able to have existing lines that set arc_max in loader.conf work
> >     correctly.
> >
> >     --
> >     Allan Jude
> >
> >
>
> The problem is related to Steven's commit, which makes it so you can
> adjust arc_max and arc_min at runtime. Part of this change put in a
> requirement that the new arc_max you are trying to set, must be less
> than the current arc_min. When you first boot, i think the default is
> arc_max = all ram save 1GB, and arc_min = 1/8 of that.
>
> So if you try to set your arc_max to 1/8th or less, it will fail with
> that error 22 (this should be fixed).
>
> You can work around it temporarily by setting a lower arc_min first.
>
>
> --
> Allan Jude
>
>