site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com I'm dealing with applications which read large (many GB, much larger than physical memory) files at a moderate rate of speed (a few MB/sec). They generally make one pass through the file and delete it. There is no benefit at all to caching the file in the kernel. The caching which is done is extremely detrimental as it causes all kinds of unnecessary paging; the OS pages out other applications which happen to be idle at the time in favor of caching the files which will never be read again. I doesn't look like Darwin/MacOSX has an O_DIRECT option to disable caching on the file at open time. Does MacOSX/Darwin have a way to disabling caching on a per-mountpoint basis? Failing that, the last Mach based OS I used (DEC OSF/1) had all kinds of nice tuning parameters to prevent the unified buffer cache from taking over too much physical memory. See, for example, the description of ubc-maxpercent at http://h30097.www3.hp.com/docs/base_doc/DOCUMENTATION/HTML/AA-Q0R3E-TET1_htm... Is there some sort of option like ubc-maxpercent in Darwin/MacOSX that I'm not seeing? Thanks, Drew _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.a... This email sent to site_archiver@lists.apple.com