From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ming Zhang Subject: Re: mdadm + raid1 of 2 disks and now need to add more Date: Tue, 11 Apr 2006 18:13:02 -0400 Message-ID: <1144793582.26235.196.camel@localhost.localdomain> References: <20060411145142.GR29446@strugglers.net> <443BE6A6.5000202@unix-scripts.info> <20060411203216.GV29446@strugglers.net> Reply-To: mingz@ele.uri.edu Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20060411203216.GV29446@strugglers.net> Sender: linux-raid-owner@vger.kernel.org To: Andy Smith Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Tue, 2006-04-11 at 20:32 +0000, Andy Smith wrote: > On Tue, Apr 11, 2006 at 07:25:58PM +0200, Laurent CARON wrote: > > Andy Smith wrote: > > >On Tue, Apr 11, 2006 at 04:41:30PM +0200, Shai wrote: > > >>I have two SCSI disks on raid1. > > >>Since I have lots of reads from that raid, I want to add two more > > >>disks to this raid so that read will be faster. > > >> > > >>How should I add the new disks? > > > > > >Is this possible with md currently: > > > > > >Create a RAID-10 on the two new disks specifying one disk missing > > >from each mirror. > > > > > >Then copy data over and add the two existing disks letting it > > >resync? > > > > Why not growing the array with 2 more disks? > > Well I guess a RAID-1 of 4 disks would be slightly more redundant > than a 4 disk RAID-10, but it would have half the capacity, and the > read performance would be very similar, no? raid1 of 4 will give u read performance like 1 disk; raid10 of 4 can give u read performance like aggregated 2 disks. >