Date: Fri, 13 Aug 2010 20:57:51 -0700 From: "Kevin Oberman" <oberman@es.net> To: TJ Varghese <tj@tjvarghese.com> Cc: stable@freebsd.org, Jeremy Chadwick <freebsd@jdc.parodius.com> Subject: Re: Inconsistent IO performance Message-ID: <20100814035751.3436F1CC3B@ptavv.es.net> In-Reply-To: Your message of "Sat, 14 Aug 2010 11:33:57 %2B0800." <AANLkTikNL3CBxC71zOktGZLXA2J1waXX6LeYwLyd7b6x@mail.gmail.com>
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> Date: Sat, 14 Aug 2010 11:33:57 +0800 > From: TJ Varghese <tj@tjvarghese.com> > > > The deviation in your disk I/O isn't a major surprise (to me anyway), > > given the system specs. What *does* surprise me is your abysmal I/O > > speeds in general. 18MB/sec min, 24MB/sec max?! ICH6-M can do a lot > > more than that. Something isn't right. > > > > > it's possible that the hw is...suboptimal. From a 2005 post, > > http://forum.thinkpads.com/viewtopic.php?f=2&t=13036&start=0 > > Check out the link to the hddbenchmark, > http://img57.imageshack.us/img57/6430/hddbenchmark1no.jpg Thanks, TJ! I guess the disk IO on these boxes simply sucks. Looks like the 34.75MB/sec sequential read speed is all I can hope for. I'm guessing the SATA-PATA converter is to blame. Oh, well. But all of this does not address my real question, why is performance so inconsistent? I agree that it sucks, but that does not explain why it suck so much worse on one run than another. I'm still baffled. My backup disk normally odes not leave my office storage cabinet except when it is in the computer being written, so I don't have it handy ATM. I will try a couple of things on Monday, though. -- R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: oberman@es.net Phone: +1 510 486-8634 Key fingerprint:059B 2DDF 031C 9BA3 14A4 EADA 927D EBB3 987B 3751
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