Date: Sat, 5 May 2001 07:02:36 -0600 (MDT) From: Doug Russell <drussell@saturn-tech.com> To: stable <stable@FreeBSD.ORG> Subject: Re: soft update should be default Message-ID: <Pine.BSF.4.21.0105050657050.94973-100000@beastie.saturn-tech.com> In-Reply-To: <200105051253.f45CrHW01020@cwsys.cwsent.com>
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On Sat, 5 May 2001, Cy Schubert - ITSD Open Systems Group wrote: > Of course as Gordon writes above, all bets are off if your disk does > write-caching. I still don't totally understand this. In the case of a drive with WCE, aren't we always assuming that the drive will correctly write the data out eventually, even if the system crashes? This assumes that we aren't talking about a power failure, here, but if it is an external drive array with dual power supplies, at least one battery backed, it doesn't matter even if the compuer power is cut, the drive should still eventually flush out it's cache, shouldn't it? (Ideal world, of course, I know.... What if the SCSI bus wedges a drive?) > There is an excellent paper entitled, Soft Updates: A Solution to the > Metadata Update Problem in File Systems, by Gergory R. Granger and Yale > N. Patt at EECS, University of Michigan. The paper is at > http://www.ece.cmu.edu/~ganger/papers/CSE-TR-254-95/. Sounds interesting... I'm going to have to go take a look.... Later....... <Doug> To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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