Date: Wed, 18 May 2016 16:43:11 +1000 From: Peter Jeremy <peter@rulingia.com> To: "Matthew D. Fuller" <fullermd@over-yonder.net> Cc: Freddie Cash <fjwcash@gmail.com>, "freebsd-fs@freebsd.org" <freebsd-fs@freebsd.org>, Steven Hartland <steven@multiplay.co.uk> Subject: Re: ZFS performance bottlenecks: CPU or RAM or anything else? Message-ID: <20160518064311.GA22800@server.rulingia.com> In-Reply-To: <20160517213549.GK24656@over-yonder.net> References: <8441f4c0-f8d1-f540-b928-7ae60998ba8e@lexa.ru> <f87ec54a-104e-e712-7793-86c37285fdaa@internetx.com> <16e474da-6b20-2e51-9981-3c262eaff350@lexa.ru> <BD7DE274-04EB-4B19-988D-5A6FADC5B51A@digsys.bg> <1e012e43-a49b-6923-3f0a-ee77a5c8fa70@lexa.ru> <86shxgsdzh.fsf@WorkBox.Home> <CAHEMsqZto0wD9Ko4E9YUpYvea4jM0E4f2nC1HkAwcCG=6DfX-A@mail.gmail.com> <CAOjFWZ6o8Gqh1BzUbkLj%2BKKXm=r2S-3qy_yk5k84Q57yj7FuAw@mail.gmail.com> <20160517213549.GK24656@over-yonder.net>
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--AqsLC8rIMeq19msA Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2016-May-17 16:35:49 -0500, "Matthew D. Fuller" <fullermd@over-yonder.ne= t> wrote: >More specifically, as I read it, different performance in a very >specific metric; single-thread linear bulk writes. That doesn't seem >like it would benefit heavily from a lot of cores available, or from >RAM bandwidth or size above a pretty low threshold. Actually, whilst I presume the OP has compression disabled, ZFS can very effectively use multiple cores to compress data - even if it's only a single linear writer. >Of course, it's not just changing the CPU and RAM; it's also the >motherboard, and possibly the HBA (at least the bus the HBA is on, if >it's a card being transplanted with the pool). And the Core 2 would >be back in the plain-old FSB era, so RAM access would be competing >with the disk IO on the bus. Without knowing much more about the configuration of each system, it's impossible to identify where the bottleneck might be. --=20 Peter Jeremy --AqsLC8rIMeq19msA Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQJ8BAEBCgBmBQJXPA7/XxSAAAAAAC4AKGlzc3Vlci1mcHJAbm90YXRpb25zLm9w ZW5wZ3AuZmlmdGhob3JzZW1hbi5uZXRFRUIyOTg2QzMwNjcxRTc0RTY1QzIyN0Ux NkE1OTdBMEU0QTIwQjM0AAoJEBall6Dkogs0kAAP/39OaH2lcRztfM/7f2QeUrLZ zBqZUEV/s5KTAWFL/enJT0Jel7pVgpGN5JZ/zKwf+SgULNZUYRVMXrJ9+9f2EkJv gi/nWwj1KgI9zLTd5W1IhOCnLe/3WXqnj+skFcmDpI69eGHI+ndBP4T6ZCG2LPSZ HjKaERFPW+cqqRnLYKsuCEVB9gZixBjV0wCkrhXoTs4d6Ce7+uFk3Wbef3EA5h8U B3bBhSdfWRIeTiJZQzq4njUmQZqQ6MAdCWUPX/EIgC0n6f6rzm4BJde8mxVilpKG BfAAl1FuBTg3zG4zI3mJ4o7lpQoNGYYVoDFmcSOMXx+TCQ1Bug8GQjN8ComViIX/ yYLMkRS0+29FUvQhNydmSuxEwQGVJmKBZNFyJqVnLNVSbbbw3hnZOwaVBxTj0hF+ BOlGh7U0JEZj7sswfD3RssljBe3PHU9qG1FYT8OSn/ScMI0lnGvVvW6XuSaujjpv SehrSwvU9HD080gbOdsGZjVI8kVzhZoejxz/GCxOf7/xqQo78kkkAXJFAOMD2fl1 gDeBijmKk+Mzf9D2QBhxByBgtyQCIDzf68sT6LNdy5od8r05rP2PXRr9TIJjiJTx MUzpxhFByrB8rdDgx3hxDbQMLpNdeif2QQNxlk4dyv1e7ic88xTisMJgJcfaa2Gm FguZKkUB0sNFjyuenM2s =gsc7 -----END PGP SIGNATURE----- --AqsLC8rIMeq19msA--
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