From owner-freebsd-isp Tue Feb 16 16:39:49 1999 Delivered-To: freebsd-isp@freebsd.org Received: from poseidon.hamsterville.ultranet.com (poseidon.hamsterville.ultranet.com [209.6.79.18]) by hub.freebsd.org (Postfix) with ESMTP id 0996D10F02 for ; Tue, 16 Feb 1999 16:39:46 -0800 (PST) (envelope-from ben@hamsterville.ultranet.com) Received: from energizer (dyn2.hamsterville.ultranet.com [209.6.79.23]) by poseidon.hamsterville.ultranet.com (8.9.1/8.9.0) with SMTP id TAA10871 for ; Tue, 16 Feb 1999 19:36:51 -0500 (EST) Message-ID: <009701be5a0e$0a8b5ce0$174f06d1@hamsterville.ultranet.com> From: "Ben Goodwin" To: References: <36C88CC6.E1621F6F@spacemonster.org> <19990216105959.P2207@lemis.com> Subject: Re: DPT 3334UW RAID-5 Slowness / Weird FS problems Date: Tue, 16 Feb 1999 19:39:55 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.2013.1300 X-Mimeole: Produced By Microsoft MimeOLE V5.00.2013.1300 Sender: owner-freebsd-isp@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org > > The user directories for delivery are broken out into 1st letter, 1st > > two letters, username (i.e.: /home/u/us/username) to speed up dir > > lookups already. > > I'd guess that these would end up in cache anyway, so you shouldn't > see much improvement with this technique. On the contrary; file-lookups are a flat scan. Breaking the lookup into a hierarchy achieves a hashing effect; with 40,000 users, my server went from (under flat-directory architecure) LA's of 4-8 and toppling over very easily on load spikes, to LA's of 0.5 to 1 and humming along w/out noticing anything. For anyone doing serious sendmail/pop activity, I highly recommend it. -=| Ben To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message