Date: Thu, 30 Dec 2010 02:31:30 -0500 From: Adam Stylinski <kungfujesus06@gmail.com> To: freebsd-stable@freebsd.org Subject: Re: slow ZFS on FreeBSD 8.1 Message-ID: <20101230073130.GA55431@zephyr.adamsnet>
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--zhXaljGHf11kAtnf Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable I can tell you what the problem is right now, actually. ZFS performs very = poorly on low performance CPUs (i.e. your Atom N330). Try the same system = with a different CPU and you'll get a different result. It's not a lack of= bandwidth on your bus, memory, or disks, and it's not exactly the checksum= ming either (although that certainly contributes to the bottleneck), the gr= ouping of transaction groups to be flushed to the disks is what your bottle= neck is. I had an issue with some fairly poor performance with a Sempron 2= 800+ 45W TDP CPU and replacing it with an Athlon X2 did wonders. =20 --zhXaljGHf11kAtnf Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (FreeBSD) iQIcBAEBAgAGBQJNHDVRAAoJED6sRHE6Tvmn66YP/ih/lpS86FVnFaTC3GxBRGa4 y7jiv9pFI1EafWcOxulxxkTAVGH6hBCodOsZbQi+aKqJH0wVfPzRXp/TFSf4CxRH EWfIAbZsouD2bRVc3/hfsCcE7nC96DB/qArY/A9lGexW6HDpzkLd5JvBwyQLbjrr qGCcnElNH8n4AMfa5zIYW2+LoD475v5dmUff21yLNFqvdJcbZN2DivF1OAxtCsbe OjZUfIrOIifdTp0YaU33zYjM74kY/lR2oa532YJiYlExELGyMY+6P4IMsBKFj/SN 2X4JKhO5uQzLU+jWYo+WyGoL4YkAWsIz1GKIMOgteD7YpEELJ82yN3qgHxRLTsKc JG6tHsIdNwbqkyccnx2sqaHkCEeM+wpub6Xvmy5r279Z8iF9bosUSKvNeZV93fEA tv2V2VmhPqhI/DZ3v4smcomqgNgFvjjpg7jlY0boaKAK7AugAGMWZpzPzKR+mEij Ltyu6uTLyWiCE4jqdIiAQphddjyhLA4/Zl8h/bkSHqXrCqmOGRcbvRlzzoIPtqts k8yY5OkOQUSNyAAE8ygnqwUT8RzkC4f7ceIAvFuORwyg7ZBNREOgqYYXW7XO21fb 9Xq9LVc1glv/jbFw7NQqZuDVtmaRUNqA17au7ouKaJtA5uX/G4hCVX4qZGEbutaY LlRNNXnFDLM+mYxW0Cdo =0WY5 -----END PGP SIGNATURE----- --zhXaljGHf11kAtnf--
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