Date: Fri, 17 Apr 1998 16:55:36 +0100 From: Karl Pielorz <kpielorz@tdx.co.uk> To: Vallo Kallaste <vallo@matti.ee> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: One more ccdconfig question Message-ID: <35377B78.95B430AE@tdx.co.uk> References: <Pine.GSO.3.96.980417182023.2197A-100000@solaris>
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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... <g> 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
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