From owner-freebsd-questions Fri Apr 17 08:56:43 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id IAA15882 for freebsd-questions-outgoing; Fri, 17 Apr 1998 08:56:43 -0700 (PDT) (envelope-from owner-freebsd-questions@FreeBSD.ORG) Received: from caladan.tdx.co.uk (caladan.tdx.co.uk [195.188.177.4]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id PAA15810 for ; Fri, 17 Apr 1998 15:56:28 GMT (envelope-from kpielorz@tdx.co.uk) Received: from tdx.co.uk (lorca-tx.tdx.co.uk [195.188.177.242]) by caladan.tdx.co.uk (8.8.8/8.8.8) with ESMTP id QAA00704; Fri, 17 Apr 1998 16:56:12 +0100 (BST) (envelope-from kpielorz@tdx.co.uk) Message-ID: <35377B78.95B430AE@tdx.co.uk> Date: Fri, 17 Apr 1998 16:55:36 +0100 From: Karl Pielorz Organization: TDX X-Mailer: Mozilla 4.04 [en] (WinNT; I) MIME-Version: 1.0 To: Vallo Kallaste CC: freebsd-questions@FreeBSD.ORG Subject: Re: One more ccdconfig question References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG This is a very good questiosn - and is liable to open a whole can of worms... In truth it is _very_ hard to work out the 'best' interleave factor for CCD... If your really worried about it - try 65536, then 32768... and see which one is faster... If you don't have the time or resources to do this - just set it to 65536... I run 2 CCD arrays on my system at the moment, one is set to 32 for the interleave - and the other is 512... I only got these figures by doing tests etc. - One thing the tests did prove out is what is an 'ideal' interleave for one type of access may not be so good for another... :-( I just went for what seemed to be the best 'all rounder' figure... I would like to think what ever figure you use (apart from some real 'oddball' ones like '1' or '2' etc.) is going to give some speed increase... Regards, Karl Pielorz Vallo Kallaste wrote: > > Hello ! > > I'm planning to use ccd on our cache server. > [snip] > Reading ccd manpage suggest interleaving factor only for news servers and > list archives contains this too. Whereas I'm not admin, but my work is > pointed to help out our admin (we are friends and work very closely) , I > don't know much about cache server real needs for disk subsystem except > this one is very disk intensive. As news server is disk intensive, too, I > think interleave factor in the range 65536 or up is enough ? > > Are there guidelines for planning interleave factor for different servers > on different disk systems (capacity, number of drives and controllers > etc.) ? There are only little remarks in the man page about it. > > Thanks > > Vallo Kallaste To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message