From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: RAID4 and RAID5 Code Date: Fri, 15 May 2009 09:19:54 -0700 Message-ID: <4A0D962A.5030309@zytor.com> References: <37d33d830905140957q6e180d89v4cd4a21d23471481@mail.gmail.com> <4A0D9384.1020805@zytor.com> <37d33d830905150914v5d780e44s6cc2174944530ddb@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <37d33d830905150914v5d780e44s6cc2174944530ddb@mail.gmail.com> Sender: linux-raid-owner@vger.kernel.org To: SandeepKsinha Cc: Linux RAID List-Id: linux-raid.ids SandeepKsinha wrote: >>> >> RAID 4 is really nothing but a block layout algorithm for RAID 5 (which >> has four more block layout algorithms.) RAID 6 contains all five under >> one "level". >> > RAID 4 vs RAID 5 > Actually debatable. They have their own pros and cons and especially > where you don't consider the physical properties of disk. > Addition of new disk, differences in speed of disks, etc.. create > bottlenecks especially in case of RAID5. > > Except hot spot issue with RAID 4, I find it better than all others. > Also, most of the proprietary solutions from IBM, Adaptec and NetApp > suggest RAID4 as compared to others. > > No offenses please, this is just an opinion. > I was talking referring to how the implementation works. However, it is still nothing but a layout policy for the same data, even though it may have quite different performance attributes. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.