From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Leslie Rhorer" Subject: RE: Considering a complete rework of RAID on my home compute server Date: Thu, 6 Jan 2011 02:10:48 -0600 Message-ID: References: <20110106054754.44e7fe1a@natsu> Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20110106054754.44e7fe1a@natsu> Sender: linux-raid-owner@vger.kernel.org To: 'Roman Mamedov' Cc: 'Mark Knecht' , 'Linux-RAID' List-Id: linux-raid.ids > On Wed, 5 Jan 2011 18:03:47 -0600 > "Leslie Rhorer" wrote: > > > RAID1 certainly offers the most robust solution, especially > > with more than 1 mirror. > > > RAID1 is as safe as it gets > > Are you sure about that? Well, yeah. > Considering that mdadm's handling of corrupt data > on > RAID1 devices is pretty simplistic (obviously it does not have per-block > checksums anywhere, it does not do 'voting' on RAID1 with more than 2 > devices), it basically has no way of knowing if a block of data is > returned Well I can't answer to that very well. Some of the other folks who are more familiar with the mechanics of the situation will have to comment, but each single member of a RAID1 array holds the entire contents of the data set. A 3N has 3 complete sets of data on it, and piecing together a fragmented data set from 3 complete sets of data is going to be more likely to produce an intact data set than from 1 + 1/N data sets. > differently by some of the component devices, which one has the 'correct' > data. From what I understand, RAID5 and especially RAID6 give a much > better > protection in this situation. It's certainly not been my experience. That said, I do run RAID6 arrays, along with RAID1 arrays. YMMV, of course.