Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261347AbUDWUey (ORCPT ); Fri, 23 Apr 2004 16:34:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261369AbUDWUey (ORCPT ); Fri, 23 Apr 2004 16:34:54 -0400 Received: from chaos.analogic.com ([204.178.40.224]:11136 "EHLO chaos.analogic.com") by vger.kernel.org with ESMTP id S261347AbUDWUew (ORCPT ); Fri, 23 Apr 2004 16:34:52 -0400 Date: Fri, 23 Apr 2004 16:34:21 -0400 (EDT) From: "Richard B. Johnson" X-X-Sender: root@chaos Reply-To: root@chaos.analogic.com To: Joel Jaeggli cc: Paul Jackson , Timothy Miller , tytso@mit.edu, miquels@cistron.nl, linux-kernel@vger.kernel.org Subject: Re: File system compression, not at the block layer In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1874 Lines: 44 On Fri, 23 Apr 2004, Joel Jaeggli wrote: > On Fri, 23 Apr 2004, Paul Jackson wrote: > > > > SO... in addition to the brilliance of AS, is there anything else that > > > can be done (using compression or something else) which could aid in > > > reducing seek time? > > > > Buy more disks and only use a small portion of each for all but the > > most infrequently accessed data. > > faster drives. The biggest disks at this point are far slower that the > fastest... the average read service time on a maxtor atlas 15k is like > 5.7ms on 250GB western digital sata, 14.1ms, so that more than twice as > many reads can be executed on the fastest disks you can buy now... of > course then you pay for it in cost, heat, density, and controller costs. > everthing is a tradeoff though. > If you want to have fast disks, then you should do what I suggested to Digital 20 years ago when they had ST-506 interfaces and SCSI was available only from third-parties. It was called "striping" (I'm serious!). Not the so-called RAID crap that took the original idea and destroyed it. If you have 32-bits, you design an interface board for 32 disks. The interface board strips each bit to the data that each disk gets. That makes the whole array 32 times faster than a single drive and, of course, 32 times larger. There is no redundancy in such an array, just brute-force speed. One can add additional bits and CRC correction which would allow the failure (or removal) of one drive at a time. Cheers, Dick Johnson Penguin : Linux version 2.4.26 on an i686 machine (5557.45 BogoMips). Note 96.31% of all statistics are fiction. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/