Date: Fri, 17 Sep 1999 10:46:08 -0500 From: Dan Nelson <dnelson@emsphone.com> To: Brad Knowles <blk@skynet.be> Cc: Thomas Dean <tomdean@ix.netcom.com>, freebsd-current@FreeBSD.ORG Subject: Re: More benchmarking stuff... Message-ID: <19990917104608.A55059@dan.emsphone.com> In-Reply-To: <v04205535b4080adcb6cf@[195.238.1.121]> References: <v0420551eb407de6b4226@[195.238.1.121]> <v04205525b407f3131c41@[195.238.1.121]> <v0420552bb40800dd5b32@[195.238.1.121]> <199909171505.IAA57153@ix.netcom.com> <v04205535b4080adcb6cf@[195.238.1.121]>
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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. 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
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