Date: Mon, 27 Jan 1997 16:53:51 +1100 From: Bruce Evans <bde@zeta.org.au> To: dicen@hooked.net, toor@dyson.iquest.net Cc: freebsd-hackers@freebsd.org Subject: Re: What is the default for async in /etc/fstab? Message-ID: <199701270553.QAA25341@godzilla.zeta.org.au>
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>> Have other people tested ufs vs. ext2? The only docs I could find where >> ... >The performance that I have measured (sequential -- IOZONE) is that >FreeBSD is faster in both read/write. However, our metadata performance >is slower (filecreates/deletes.) With -async, our metadata is still >slower, but not by orders of magnitude. FreeBSD's cache perf is much >faster (by factors of 3-4.) Much of it is due to the default block >size (8K vs. 1K.) But the fragment size of an 8K UFS filesystem is >the *same* as a 1K ext2fs. In my tests, ext2fs is fastest for huge sequential i/o's when the block sizes are closer (8K vs 4K), but there was only a small difference (less than 10%) between the best and worst cases (best: ext2fs under FreeBSD, next: ext2fs under Linux, worst: ext2fs under Linux) except for rewrite, which was 66% faster under Linux than under FreeBSD. Cache performance also catches up (46MB/sec for FreeBSD-current-last-November, 41MB/sec for Linux-2.0.20). A 4K fragment size wastes space probably wastes time in most cases. Bruce
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