Date: Tue, 20 May 2008 16:38:29 -0700 From: Xin LI <delphij@delphij.net> To: Andrew Snow <andrew@modulus.org> Cc: freebsd-scsi@freebsd.org, d@delphij.net Subject: Re: Very poor performance from Dell/LSI Logic SAS 3000 series SATA/SAS RAID controller FreeBSD 6.3 Message-ID: <483360F5.6090404@delphij.net> In-Reply-To: <48335FD5.3000800@modulus.org> References: <4832C397.3090004@calorieking.com> <4832E0EE.3030402@samsco.org> <4832E6C2.7040205@calorieking.com> <4833483B.4030208@modulus.org> <4833595D.1070409@delphij.net> <48335FD5.3000800@modulus.org>
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Andrew Snow wrote: | Xin LI wrote: |> I believe that data corruption can happen on every place if writing |> cache is lost, it's not an UFS-specific feature :) | | ZFS has the promise of not requirring safe hardware write-caches due to | its parity data and intent log. | | From my understanding, it can promise that a data block has been | written completely and safely, and that filesystem metadata is not | corrupted, but out-of-order writes could still happen. ZFS's promise is based on the fact that it does not overwrite data. Oops, I think I should not use the term 'corruption', I meant 'loss'. Cheers, - -- ** Help China's quake relief at http://www.redcross.org.cn/ |>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Xin LI <delphij@delphij.net> http://www.delphij.net/ FreeBSD - The Power to Serve! -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (FreeBSD) iEYEARECAAYFAkgzYPUACgkQi+vbBBjt66CSsgCgsWfChktCt/XfocU/olHV1OSZ jq0An0NZaQOp8fJcxhS3YB2z3Wp7va3E =5a34 -----END PGP SIGNATURE-----
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