Date: Wed, 17 Jul 2002 11:26:48 -0700 From: Dave Hayes <dave@jetcafe.org> To: Andrew Heybey <ath@niksun.com> Cc: freebsd-scsi@FreeBSD.ORG Subject: Re: Random hangs on (at least) SCSI reads Message-ID: <200207171826.g6HIQr049869@hokkshideh2.jetcafe.org>
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Andrew Heybey <ath@niksun.com> writes: > What motherboard? Exactly how does it lock up? Is there anything > else going on on the machine at the time? Intel D845GLAD. It locks up with the HDD light frozen on. > I ask because we have seen hard lockups on an Intel STL2 > motherboard. A PCI bus analyzer on the bus sees the disk controller > vainly trying to do a memory read or write and being told to retry > by the chipset. We have seen these with 4.2 and with 4.5. Well we've isolated the problem (we think). These machines are built using a 2U case. This requires a PCI riser card that plugs into the motherboard PCI slot and provides horizontal (rather than vertical) card mounting options. With that riser card out, I've run the same "crashme" script which puts a moderate to heavy load on the disk subsystem, and the machine is still up (16 hours and counting). Electronically speaking that riser card adds a extra capacitance and resistance that is probably not in the design spec for PCI. That's the current theory anyway. I don't know enough about PCI to know if that makes sense or not. I do know we are going to try slowing down the SCSI transfer speed to see if that helps any. Other ideas and commentary are more than welcome. =) ------ Dave Hayes - Consultant - Altadena CA, USA - dave@jetcafe.org >>> The opinions expressed above are entirely my own <<< Because you grasp labels and slogans, you are hindered by those labels and slogans, both those used in ordinary life and those considered sacred. Thus they obstruct your perception of objective truth, and you cannot understand clearly. -Zen Master Linji To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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