Date: Thu, 17 Jan 2013 21:51:34 -0800 From: Adrian Chadd <adrian@freebsd.org> To: Dieter BSD <dieterbsd@gmail.com> Cc: freebsd-hackers@freebsd.org, gibbs@freebsd.org, scottl@freebsd.org, mjacob@freebsd.org Subject: Re: IBM blade server abysmal disk write performances Message-ID: <CAJ-Vmo=TX0cUttQa_x7a-WU=yqo_Zjedzcbn5dibihFvDXRaNg@mail.gmail.com> In-Reply-To: <CAA3ZYrCgMmGi3EHKEuXb=qWPjC2zSMYcfgZ6nh-ipqQ7dAeVdA@mail.gmail.com> References: <CAA3ZYrCgMmGi3EHKEuXb=qWPjC2zSMYcfgZ6nh-ipqQ7dAeVdA@mail.gmail.com>
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When you run gstat, how many ops/sec are you seeing? Adrian On 17 January 2013 20:03, Dieter BSD <dieterbsd@gmail.com> wrote: >> I am thinking that something fancy in that SAS drive is >> not being handled correctly by the FreeBSD driver. > > I think so too, and I think the something fancy is "tagged command queuing". > The driver prints "da0: Command Queueing enabled" and yet your SAS drive > is only getting 1 write per rev, and queuing should get you more than that. > Your SATA drive is getting the expected performance, which means that NCQ > must be working. > >> Please let me know if there is anything you would like me to run on the >> BSD 9.1 system to help diagnose this issue? > > Looking at the mpt driver, a verbose boot may give more info. > Looks like you can set a "debug" device hint, but I don't > see any documentation on what to set it to. > > I think it is time to ask the driver wizards why TCQ isn't working, > so I'm cc-ing the authors listed on the mpt man page. > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org"
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