Date: Sun, 24 Jan 1999 01:49:14 -0800 From: David Greenman <dg@root.com> To: Greg Lehey <grog@lemis.com> Cc: jm7996@devrycols.edu, Konrad Heuer <kheuer@gwdu60.gwdg.de>, freebsd-advocacy@FreeBSD.ORG Subject: Re: FreeBSD - A User's Point of View Message-ID: <199901240949.BAA17434@implode.root.com> In-Reply-To: Your message of "Sun, 24 Jan 1999 20:15:56 %2B1030." <19990124201556.E36690@freebie.lemis.com>
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>>> I'd be a whole lot happier if people wouldn't make statements like >>> this. If it's evil, explain. If you don't know any good reasons, >>> don't spread misinformation. >> >> The Linux filesystem, or ext2fs, if I'm not mistaken by default caches >> writes to the disk. If the machine should suddenly go down, power >> failure, unexpected crash, etc..., this information doesn't make it back >> to the disk. I've known many a Linux user who has lost _entire_ file >> systems due to this. > >UFS does this too. Uh, he's talking about metadata, and no FFS does not cache metadata writes by default. >> It surprises me that the Linux vendors don't turn this 'feature' off by >> default. They could include in the doc's an explanation of why it's >> turned off and give the users instructions on how to turn it back on, if >> they like. > >I don't know if it's possible to turn it off in Linux. You can't turn >it off in UFS either. In fact, the manner in which disk writes are >cached is pretty central to FreeBSD's performance. Actually, prior to softupdates, FreeBSD's filesystem performance wasn't very good compared to ext2fs for the very reason that ext2fs is "fast and loose" by defering metadata writes. This has the downside of making ext2fs filesystem integrity unreliable in the face of a system crash or power failure. FFS does not have this problem, but is much slower as a result. -DG David Greenman Co-founder/Principal Architect, The FreeBSD Project To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-advocacy" in the body of the message
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