From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: Re: The effects of multiple layers of block drivers Date: Fri, 11 Jan 2008 12:45:07 +1100 Message-ID: <18310.51747.929398.385256@notabene.brown> References: <4786A329.90702@2inches.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: message from Dennison Williams on Thursday January 10 Sender: linux-raid-owner@vger.kernel.org To: Dennison Williams Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Thursday January 10, evoltech@2inches.com wrote: > Hello, > > I am starting to dig into the Block subsystem to try and uncover the > reason for some data I lost recently. My situation is that I have > multiple block drivers on top of each other and am wondering how the > effectss of a raid 5 rebuild would affect the block devices above it. It should "just work" - no surprises. raid5 is just a block device like any other. When doing a rebuild it might be a bit slower, but that is all. > > The layers are raid 5 -> lvm -> cryptoloop. It seems that after the > raid 5 device was rebuilt by adding in a new disk, that the cryptoloop > doesn't have a valid ext3 partition on it. There was a difference of opinion between raid5 and dm-crypt which could cause some corruption. What kernel version are you using, and are you using dm-crypt or loop (e..g losetup) with encryption? > > As a raid device re-builds is there ant rearranging of sectors or > corresponding blocks that would effect another block device on top of it? No. NeilBrown