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Date:      Wed, 6 Jul 2016 02:20:57 -0400
From:      Nathan Bosley <nathan.bosley@gmail.com>
To:        Allan Jude <allanjude@freebsd.org>
Cc:        freebsd-current@freebsd.org
Subject:   Re: Setting sysctl vfs.zfs.arc_max failed: 22
Message-ID:  <CAB%2BRvm63pnLSx-fX8kiZp5Q%2BMB424xnAZeXRAr-de%2BEHiW1XCQ@mail.gmail.com>
In-Reply-To: <CAB%2BRvm4V88ppSdFJ-DsUf6AKx6UC=hdbA_r4LjMdtwLCRa9pVw@mail.gmail.com>
References:  <ccdd6a5b-4771-6207-adb3-ce9a7960485c@FreeBSD.org> <975e5ae2-2090-94cd-49c0-eee9866ff02b@freebsd.org> <CAB%2BRvm7c97ionaM02UgTLNt-aqQJLZ8%2B5ZoFL9gHDhmmx=cCcg@mail.gmail.com> <e1fd9ae9-71de-ec0f-53d2-1c5d2f9ccc87@multiplay.co.uk> <145180d1-43c9-d894-9221-b210d641955d@freebsd.org> <CAB%2BRvm6OpDQMz4vE7d0D76wDuPjzh597UaDXjNfrHLP59st_ag@mail.gmail.com> <7255f240-8cf0-0a62-89be-2a0970b67063@freebsd.org> <CAB%2BRvm4V88ppSdFJ-DsUf6AKx6UC=hdbA_r4LjMdtwLCRa9pVw@mail.gmail.com>

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Maybe I misunderstood after all.
I took this:
"You can work around it temporarily by setting a lower arc_min first."

To mean that I could do something like:
vfs.zfs.arc_min="1073741824"
vfs.zfs.arc_max="8589934592"

in loader.conf, which would circumvent the problem.
But with the above, in that order, I still get:

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

As an FYI, WITHOUT any tunables set, my defaults are:
vfs.zfs.arc_meta_limit: 3903459328
vfs.zfs.arc_min: 1951729664
vfs.zfs.arc_max: 15613837312

So even if I only specified:
vfs.zfs.arc_max="8589934592"

in loader.conf, that's still not below my default min.

However, if I make the changes with 'sysctl' after boot, it works fine:

root@athlonbsd:~ # sysctl vfs.zfs.arc_min="1073741824"
vfs.zfs.arc_min: 1951729664 -> 1073741824

root@athlonbsd:~ # sysctl vfs.zfs.arc_max="8589934592"

vfs.zfs.arc_max: 15613837312 -> 8589934592

They also work fine sysctl.conf.

Sorry if this is a silly question:
I should still be able to set these max/min values in loader.conf,
right--not just in sysctl.conf?

Thanks.


On Tue, Jul 5, 2016 at 10:16 PM, Nathan Bosley <nathan.bosley@gmail.com>
wrote:

> 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@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@freebsd.org
>> > <mailto:allanjude@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@multiplay.co.uk <mailto:steven@multiplay.co.uk>
>> >     <mailto:steven@multiplay.co.uk <mailto:steven@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 @ 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
>> >     >>
>> >     >>
>> >     >>     _______________________________________________
>> >     >>     freebsd-current@freebsd.org
>> >     <mailto:freebsd-current@freebsd.org>
>> >     <mailto:freebsd-current@freebsd.org
>> >     <mailto:freebsd-current@freebsd.org>>
>> >     >>     mailing list
>> >     >>     https://lists.freebsd.org/mailman/listinfo/freebsd-current
>> >     >>     To unsubscribe, send any mail to
>> >     >>     "freebsd-current-unsubscribe@freebsd.org
>> >     <mailto:freebsd-current-unsubscribe@freebsd.org>
>> >     >>     <mailto:freebsd-current-unsubscribe@freebsd.org
>> >     <mailto:freebsd-current-unsubscribe@freebsd.org>>"
>> >     >>
>> >     >>
>> >     >
>> >     > _______________________________________________
>> >     > freebsd-current@freebsd.org <mailto:freebsd-current@freebsd.org>
>> >     mailing list
>> >     > https://lists.freebsd.org/mailman/listinfo/freebsd-current
>> >     > To unsubscribe, send any mail to "
>> freebsd-current-unsubscribe@freebsd.org
>> >     <mailto:freebsd-current-unsubscribe@freebsd.org>"
>> >
>> >
>> >     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
>>
>>
>



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