Date: Tue, 27 Mar 2007 19:58:48 +0200 From: Ivan Voras <ivoras@fer.hr> To: freebsd-stable@freebsd.org Subject: Re: Dell SAS5 Performance Issue Message-ID: <eubm0p$bo7$1@sea.gmane.org> In-Reply-To: <460959E8.207@thekeelecentre.com> References: <460959E8.207@thekeelecentre.com>
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[-- Attachment #1 --] Richard Tector wrote: > I'm suffering from very slow write performance on a Dell PowerEdge 860 > with the SAS5/IR controller (mpt driver) running either 6.2-RELEASE or > 6.2-STABLE with sources from yesterday. The controller hosts 2 Western > Digital 320GB SATA disks in a RAID1 configuration. > Reads approach 65MB/s however writes appear extremely slow, in the > region of 6-7MB/s with a dd and a blocksize of 1MB all the way down to > about 300KB/s while extracting a ports snapshot. > > It was suggested to me that perhaps write caching has been disabled on > the controller however no options exist within the BIOS configuration to > view/adjust *any* caching options. You looked in the controller's BIOS, not motherboard's, right? There should be at least a "write through" vs "write back" switch... If you don't have a battery for the SAS controller, get one. > Has anyone else experienced this issue? No, but can you post the relevant bits for the controller from dmesg? [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.4 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGCVtZldnAQVacBcgRAg1/AKDp+fq/AP6tqq6EkCCAJ4TarfeL5ACg2vaK YvdKtSmUyZU+2Cxxsa1lTVU= =IXhb -----END PGP SIGNATURE-----
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