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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[-- Attachment #1 --] 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 checksumming either (although that certainly contributes to the bottleneck), the grouping of transaction groups to be flushed to the disks is what your bottleneck is. I had an issue with some fairly poor performance with a Sempron 2800+ 45W TDP CPU and replacing it with an Athlon X2 did wonders. [-- Attachment #2 --] -----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-----
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