From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965332AbXCFQqX (ORCPT ); Tue, 6 Mar 2007 11:46:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965920AbXCFQqX (ORCPT ); Tue, 6 Mar 2007 11:46:23 -0500 Received: from mail.tmr.com ([64.65.253.246]:58839 "EHLO gaimboi.tmr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965332AbXCFQqW (ORCPT ); Tue, 6 Mar 2007 11:46:22 -0500 Message-ID: <45ED9B5B.2030806@tmr.com> Date: Tue, 06 Mar 2007 11:48:27 -0500 From: Bill Davidsen User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.8) Gecko/20061105 SeaMonkey/1.0.6 MIME-Version: 1.0 Newsgroups: gmane.linux.kernel To: Marc Perkel CC: Jan Engelhardt , linux-kernel@vger.kernel.org Subject: Re: Raid 10 Problems? References: <382470.25191.qm@web52508.mail.yahoo.com> In-Reply-To: <382470.25191.qm@web52508.mail.yahoo.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Marc Perkel wrote: > --- Jan Engelhardt wrote: > >> On Mar 4 2007 19:17, Marc Perkel wrote: >>> Thanks - because of your suggestion I had found the >>> instructions. But you have some interesting options >>> set. >>> >>> -N nicearray -b internal -e 1.0 >>> >>> Are these important? >> -N? What's in a name? I suppose, it's not so >> important. >> (Arrays are identified by their UUID anyway. But >> maybe >> udev can do something with the name someday as it >> does >> today with /dev/disk/*.) > > Not worth starting over for. > >> -b internal -- seems like a good idea to speed up >> resynchronization. > > I'm trying to figure out what the default is. > >> -e 1.0 -- I wonder why the new superblock format >> is >> not default in mdadm (0.90 is still used). >> > > Looks interesting for big arrays but not sure it's > worth starting over for. Trying to get through a 2 > hour sync using 4 500gb sata 2 drives. That's exactly why you want the bitmap. Fortunately you can add it after the array is created. Now the bad news, you should read and understand the meaning of the "far" layout. Part of the information is in the mdadm man page under -p, some in the md man page. Use of "far" layout will effect the performance of the array, the balance of read vs. write performance, and (maybe) the reliability. Two hours is a pretty short time to invest if you find that you have your layout wrong and would be better off for the life of the array with some other data layout. And the time to do the reading is worth if if you wind up convinced that the default settings are fine for you. -- Bill Davidsen "We have more to fear from the bungling of the incompetent than from the machinations of the wicked." - from Slashdot