Date: Fri, 17 Sep 1999 08:55:59 -0700 (PDT) From: Julian Elischer <julian@whistle.com> To: Dan Nelson <dnelson@emsphone.com> Cc: Brad Knowles <blk@skynet.be>, Thomas Dean <tomdean@ix.netcom.com>, freebsd-current@FreeBSD.ORG Subject: Re: More benchmarking stuff... Message-ID: <Pine.BSF.4.05.9909170855210.13667-100000@home.elischer.org> In-Reply-To: <19990917104608.A55059@dan.emsphone.com>
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On Fri, 17 Sep 1999, Dan Nelson wrote: > In the last episode (Sep 17), Brad Knowles said: > > At 8:05 AM -0700 1999/9/17, Thomas Dean wrote: > > > Are the files deleted before they are actually written to disk? > > > > Good question. I don't know the answer. I know that the > > process is to create all the files first, then operate on them > > (including deletions and more creations), and then finally do a > > removal of all of them as quickly as possible at the end of the test. > > > > I'd be willing to guess a lot of files do get created and then > > deleted before the data ever gets written to disk. After all, > > postmark was written to simulate the kind of a load that a > > heavily-used mail system places on the machine, and that's precisely > > the sort of environment where something like softupdates or mounting > > filesystems async does tend to help the most. > > Hmm. But when you're running a mail spool, you _want_ your files to > get committed to disk, don't you? If you've got (guessing) 500 spool > files sitting in unflushed disk caches and you reboot, those files are > lost. Softupdated just guarantees that the disk will be in a stable > state after a crash, not that all data written before the crash will be > available. > Soft updates guarantees that when an fsync() is done, it's on disk... > Don't NetApps do logging, so if the system crashes, the files are > recovered from the log? > > -- > Dan Nelson > dnelson@emsphone.com > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-current" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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