Date: Fri, 26 Aug 2016 17:48:49 +0200 From: Ben RUBSON <ben.rubson@gmail.com> To: FreeBSD FS <freebsd-fs@freebsd.org> Subject: Re: [ZFS] ARC accounting bug ? Message-ID: <D8D82933-0455-40BE-8D22-8DCB9B158251@gmail.com> In-Reply-To: <453b967d-4139-c6b6-a27a-223ed4d92c74@kateley.com> References: <C2642B73-83F2-4A1C-88BE-322F376861FF@gmail.com> <5B8C6663-5D21-4C03-AC69-CB7E70D3A6C2@gmail.com> <067ac0ed-1f2d-c9fb-de4d-ed5da62fe10c@internetx.com> <9EAAEEC5-0FFF-474D-9AD0-4447CD6B549B@gmail.com> <c45b36de-b43f-6eae-4187-142f1e5c3e48@internetx.com> <91665D7B-D2EA-4A7F-BE8D-67BE238DAF6B@gmail.com> <9A3B2699-B077-4F72-90A5-63D7E22BE652@gmail.com> <453b967d-4139-c6b6-a27a-223ed4d92c74@kateley.com>
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Linda, Thank you very much for your suggestion. However atime is off on my pool. > On 26 Aug 2016, at 17:46, Linda Kateley <lkateley@kateley.com> wrote: > > Metadata updates when you access a file. Atime is most often updated and you will miss. > > If you are running vm's on zfs I always recommend to turn off atime updates. > > Metadata is usually tiny so you probably won't see disk activity > > > On 8/26/16 10:27 AM, Ben RUBSON wrote: >> I'm sorry but I still can't find out where do these ARC demand metadata misses come from. >> In addition, why they are not cached, as my ARC is 1% used. >> And why I don't see any disk activity to honour them. >> >> I would really be glad if you could enlighten me :) >> >> Many thanks again, >> >> Ben >> >> >> >>> On 26 Aug 2016, at 14:28, Ben RUBSON <ben.rubson@gmail.com> wrote: >>> >>> Yes Juergen, metadata only stores in ARC files' info (location in pool and some other useful info), not the user data. >>> >>> I think "find" only needs metadata, as it does not read the files' content. >>> Which can be "verified" because : >>> - there is no IO at all on the pool (after the first find loop, once ARC has the needed metadata) ; >>> - there is no ARC demand data at all. >>> But I may be wrong, so of course feel free to correct me. Thank you. >>> >>> Thank you for the links, I already read them before posting here, but I may have missed something. >>> >>> Ben >>> >>>> On 26 Aug 2016, at 14:16, InterNetX - Juergen Gotteswinter <juergen.gotteswinter@internetx.com> wrote: >>>> >>>> so, you know the difference between >>>> >>>> - metadata >>>> - data >>>> >>>> ? >>>> >>>> if yes, what is your find actually doing in this case? >>>> >>>> regarding arc >>>> >>>> http://dtrace.org/blogs/brendan/2012/01/09/activity-of-the-zfs-arc/ >>>> https://www.patpro.net/blog/index.php/2014/03/19/2628-zfs-primarycache-all-versus-metadata/ >>>> >>>> >>>> >>>> Am 26.08.2016 um 14:06 schrieb Ben RUBSON: >>>>> Juergen, thank you for your answer. >>>>> So where do you think these ARC misses come from ? I can't find out :S >>>>> Thank you ! >>>>> >>>>>> On 26 Aug 2016, at 14:01, InterNetX - Juergen Gotteswinter <juergen.gotteswinter@internetx.com> wrote: >>>>>> >>>>>> no bug, everything like i whould expect >>>>>> >>>>>> Am 26.08.2016 um 11:40 schrieb Ben RUBSON: >>>>>>> uname -v >>>>>>> FreeBSD 11.0-RC2 #0 r304729: Wed Aug 24 06:59:03 UTC 2016 root@releng2.nyi.freebsd.org:/usr/obj/usr/src/sys/GENERIC >> _______________________________________________ >> freebsd-fs@freebsd.org mailing list >> https://lists.freebsd.org/mailman/listinfo/freebsd-fs >> To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" > > _______________________________________________ > freebsd-fs@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org"
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