Date: Mon, 19 Oct 1998 12:04:00 -0600 From: "Justin T. Gibbs" <gibbs@plutotech.com> To: Terry Lambert <tlambert@primenet.com> Cc: julian@whistle.com, guido@gvr.org, dkelly@hiwaay.net, freebsd-fs@FreeBSD.ORG, freebsd-scsi@FreeBSD.ORG Subject: Re: filesystem safety and SCSI disk write caching Message-ID: <199810191810.MAA06527@pluto.plutotech.com> In-Reply-To: Your message of "Mon, 19 Oct 1998 17:47:39 -0000." <199810191747.KAA28054@usr02.primenet.com>
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>> >Perhaps they realized that the mpst likely event after a power >> >fluctuation was a bus reset, and figured "why bother?". >> >> And why is this relevant? The only reasons allowed for cache contents >> never making it to the disk are power loss and hardware failure. A >> bus reset (assuming the hard reset alternative is in effect) only clears >> any transactions that have not been reported as completed to the host. >> >> Perhaps you should add the SCSI II and SCSI II specs to your list of things >> to read. > >Feel free to engage in Ad Hominim attacks... If it was an attack, it was self-inflicted. You should know better than to make statements on topics you do not fully comprehend. It is blatantly obvious to anyone who has read the spec that you either have not read the spec or did not comprehend it. It is only fair to ensure that the less informed people on this list know that you are anything but an expert on SCSI and they should take you comments as uninformed supposition at best. If you don't want to be 'attacked' stop throwing FUD around on our lists. >, *after* you explain why >Don Lewis is seeing the empirical behaviour he is seeing, in >contradiction to your claims of what's possible and not. I've already given my opinion on this. I believe the Hawk is seeing a power glitch or temporary power loss when the reset switch is hit and so the contents of the cache are lost. I have never said that the behavior that Don Lewis is seeing is 'not possible', only that, for the drive in question, the reset causing cache corruption is not likely. Pluto has validated the Hawk for use in our RAID 3 systems, and part of this validation includes spurious bus resets. This behavior was never encountered in our tests. -- Justin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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