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Path: sserve!newshost.anu.edu.au!harbinger.cc.monash.edu.au!bunyip.cc.uq.oz.au!munnari.oz.au!spool.mu.edu!howland.reston.ans.net!agate!library.ucla.edu!psgrain!charnel.ecst.csuchico.edu!xmission!u.cc.utah.edu!cs.weber.edu!terry From: terry@cs.weber.edu (Terry Lambert) Newsgroups: comp.unix.bsd Subject: Re: Write-Through the File System Cache? Date: 20 Aug 1994 08:30:37 GMT Organization: Weber State University, Ogden, UT Lines: 30 Message-ID: <334evd$mgn@u.cc.utah.edu> References: <3305rj$14k@hopper.acm.org> NNTP-Posting-Host: cs.weber.edu In article <3305rj$14k@hopper.acm.org> ian_vogt@ACM.ORG writes: ] ] re: BSDI (but also for others in the *BSD* family) ] ] I would like to know if it is possible (without modifying ] the kernel) for an application to disable delayed write ] caching (or enable write-through caching) either for the ] file system as a whole or for a particular file (or file ] handle). ] ] I develop fault tolerant applications requiring that ] critical file updates be committed to disk before returning ] from the write call (for recovery purposes). This behaviour is already guaranteed by UFS for metadata; for non-metadata, you should use the O_WRITESYNC flag when opening (there is, I believe, a bug in dir.c where an async write should be a sync write in NetBSD and FreeBSD). If you can guarantee atomicity of request ordering from user space (ie: a single user space consumer for the interface for your engine), then you might also be able to use fsync(2). Terry Lambert terry@cs.weber.edu --- Any opinions in this posting are my own and not those of my present or previous employers.