From owner-freebsd-hackers Mon May 28 11: 8:58 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from a.mx.everquick.net (a.mx.everquick.net [216.89.137.3]) by hub.freebsd.org (Postfix) with ESMTP id 2CB0F37B422 for ; Mon, 28 May 2001 11:08:55 -0700 (PDT) (envelope-from eddy+public+spam@noc.everquick.net) Received: from localhost (eddy@localhost) by a.mx.everquick.net (8.10.2/8.10.2) with ESMTP id f4SI8sS06427 for ; Mon, 28 May 2001 18:08:54 GMT X-EverQuick-No-Abuse: Report any e-mail abuse to Date: Mon, 28 May 2001 18:08:53 +0000 (GMT) From: "E.B. Dreger" To: hackers@FreeBSD.ORG Subject: Re: brainstorm: "intermediate" disk caching In-Reply-To: <3B128FB4.70AE7C69@i-clue.de> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG > Date: Mon, 28 May 2001 19:49:40 +0200 > From: Christoph Sold > >> My gut feel is that this would be more trouble than it's worth, would >> not net any overall performance*reliability (expressed as a >> product) gain, and that one might actually realize a p*r decrease. > > IMHO it would speed up your DB significantly to have it a) run on a RAID > 10 array and b) have it run on the raw disk. Two layers of lag reduced > (well, for reads it is possibly only one layer). RAID 1+0 is what I use... but I was thinking of scalibility. In a five- drive array (using one as a hot spare), RAID 1+0 has 67% the capacity of RAID 5. More expensive per megabyte, but handles more db ops. However, the numbers become less favorable with bigger RAID 1+0 arrays. Also, intermediate caching *does not* inherently defeat the purpose of RAID. IO could be cached to a RAID 1 volume, then transferred to the RAID 5 volume... my question was if it was worth the hassle. Of course, with 36 GB drives readily available, maybe I shouldn't worry until I have a database larger than 72 GB. ;-) Eddy --------------------------------------------------------------------------- Brotsman & Dreger, Inc. EverQuick Internet Division Phone: (316) 794-8922 --------------------------------------------------------------------------- Date: Mon, 21 May 2001 11:23:58 +0000 (GMT) From: A Trap To: blacklist@brics.com Subject: Please ignore this portion of my mail signature. These last few lines are a trap for address-harvesting spambots. Do NOT send mail to , or you are likely to be blocked. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message