Date: Mon, 2 Oct 2006 14:08:10 +0100 (BST) From: Chris Hedley <cbh-freebsd-current@groups.chrishedley.com> To: current@freebsd.org Subject: Re: aac0: COMMAND 0xffffffffxxxxxxxx TIMEOUT AFTER xx SECONDS Message-ID: <20061002134625.X1531@teapot.cbhnet> In-Reply-To: <C2F12CFF-B6C8-4DE1-A76F-7210155EF0A1@shire.net> References: <20060609163735.D829@aga.cbhnet> <20060609120159.I60598@carver.gumbysoft.com> <20060609202536.Y829@aga.cbhnet> <4489D796.4010202@samsco.org> <20060611122544.L1046@aga.cbhnet> <C2F12CFF-B6C8-4DE1-A76F-7210155EF0A1@shire.net>
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On Sun, 11 Jun 2006, Chad Leigh -- Shire.Net LLC wrote: > On Jun 11, 2006, at 5:41 AM, Chris Hedley wrote: >> I'm starting to get the impression that the 2410SA's low end design is even >> lower than its fairly low-end price would suggest. Any suggestions for >> similarly priced cards with better performance? The best I can manage for >> slot type is 66x64 PCI unless I change my motherboard, which I can't quite >> afford to do at the moment... > > I have not done any performance testing but I have some LSI MegaRAID SATA-150 > 4 cards. Maybe you can find some benchmark comparison reviews. The Areca, > which is a bit more expensive, also gets good reviews. I have a couple of > them but for my Solaris 10 machines and they are just now being set up. Both > the LSI and Areca have FreeBSD drivers. Must admit I'm tempted by an Areca, even with the high price tag. I've been having a look at some reviews, but unfortunately few of them make it clear whether or not the hard drives' cache is set to write back or write through. Needless to say, I'm not desperately enthusiastic about combining a RAID controller with write back caching, but I suspect that a lot of controllers are heavily dependent on it being enabled to attain their performance: it seems that my 2410SA's rather dismal 3-6 & 30-40MB/s respective RAID5 write & read speeds would increase dramatically were I to use write-back, but I'm not going there... I guess my point is that I really don't want to find myself with another dog if I buy something with apparently superior performance if it's completely reliant on on-disc write back caching being enabled. Does anybody know of any good review sites featuring controllers such as those that Chad mentions where the reviewers definitely had on-disc write back disabled? The reason I'm asking is after reading reviews on, for example, xbitlabs.com, where the comment "We also enabled lazy writing for the hard disk drives" is almost added as an afterthought and isn't immediately obvious. Exactly why they chose to enable it is a matter for another debate, I guess... I'm really desperate to ditch the 2410SA controller: the performance, as mentioned, is terrible, and it tends to lock up the entire system with various timeouts if anything more than trivial read or write accesses are attempted (not sure if this is the case with the latest -current as I've been having too many problems with assorted panics with recent kernels to test it fully). Cheers, Chris.
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