Date: Mon, 31 Mar 2003 08:45:11 +0930 From: Greg 'groggy' Lehey <grog@FreeBSD.org> To: Lukas Ertl <l.ertl@univie.ac.at> Cc: freebsd-stable@freebsd.org Subject: Re: vinum performance Message-ID: <20030330231511.GF1861@wantadilla.lemis.com> In-Reply-To: <20030330175605.E23911@leelou.in.tern> References: <20030330125138.K23911@leelou.in.tern> <3E870CC7.5000204@mac.com> <20030330175605.E23911@leelou.in.tern>
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--rWhLK7VZz0iBluhq Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Sunday, 30 March 2003 at 18:00:01 +0200, Lukas Ertl wrote: > On Sun, 30 Mar 2003, Chuck Swiger wrote: > >> Lukas Ertl wrote: >> [ ... ] >> Also, what tasks you intend to use the RAID filesystem for are critical >> to consider, even if the answer is simply "undifferentiated >> general-purpose storage". In particular, RAID-5 write performance is >> going to be slow, even with RAID hardware support which offloads the >> parity calculations from the system CPU(s). RAID-5 is best suited for >> read-mostly or read-only volumes, where you value cost more than >> performance. > > Ok. But I still don't understand why RAID 5 write performance is > _so_ bad. That's certainly something to investigate. > The CPU is not the bottle neck, it's rather bored. And I don't > understand why RAID 0 doesn't give a big boost at all. What can it do? You're only writing one file at a time. > Is the ahc driver known to be slow? This is definitely not a driver performance issue. Greg -- See complete headers for address and phone numbers --rWhLK7VZz0iBluhq Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.0 (FreeBSD) iD8DBQE+h3p/IubykFB6QiMRAlsGAKCfKN+iary86RtrBLQ9vnH4nhqxlwCaAsuv zOGzm9ELJCWnh+DliUmiqJw= =QKX1 -----END PGP SIGNATURE----- --rWhLK7VZz0iBluhq--
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