Date: Thu, 17 Feb 2005 15:18:53 -0600 From: Eric Anderson <anderson@centtech.com> To: Chuck Swiger <cswiger@mac.com> Cc: current@freebsd.org Subject: Re: where did all my memory go? (file system cache) Message-ID: <42150A3D.8080500@centtech.com> In-Reply-To: <4214FD67.7060801@mac.com> References: <1108584730.95661.12.camel@server.mcneil.com> <20050216201716.GA28436@odin.ac.hmc.edu> <4213B3C8.3090508@centtech.com> <1108588393.12275.9.camel@server.mcneil.com> <20050216214031.GA2787@odin.ac.hmc.edu> <4213D3AA.70809@elischer.org> <84dead72050217081540fd7640@mail.gmail.com> <4214FD67.7060801@mac.com>
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Chuck Swiger wrote: > Joseph Koshy wrote: > >>> what I want is: >>> >>> int fd = open("myfile",...); >>> write1GBfiletodisk(fd, data); >>> ioctl(fd, PURGEFROMCACHE); >>> perform_md5(fd); >>> >>> and be sure that teh MD5 is that of what is on the disk. >>> not what is in RAM. >> >> >> unmount(file-system-of("myfile")) (even if it fails) ? > > > That's actually a pretty good suggestion, and is less intrusive than, > say rebooting, which is probably the only way to be entirely sure that > the write cache on the drive itself has been flushed. If the write > cache is off, Julian probably ought to be able to trust fsync(2)...? Wouldn't there be a way to take the code that does the cache dumping (excuse my bad lingo here) and make a little tool that does it without any actual unmounting? Suppose the filesystem actually unmounted.. yikes! Eric -- ------------------------------------------------------------------------ Eric Anderson Sr. Systems Administrator Centaur Technology I have seen the future and it is just like the present, only longer. ------------------------------------------------------------------------
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