From mboxrd@z Thu Jan 1 00:00:00 1970 References: <5735AEE4.4080402@assyoma.it> <20160516185518.GA3320@redhat.com> From: Gionatan Danti Message-ID: <573B1A13.7050006@assyoma.it> Date: Tue, 17 May 2016 15:18:11 +0200 MIME-Version: 1.0 In-Reply-To: <20160516185518.GA3320@redhat.com> Content-Transfer-Encoding: 7bit Subject: Re: [linux-lvm] Backup superblock for thin provision? Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Mike Snitzer Cc: LVM general discussion and development On 16/05/2016 20:55, Mike Snitzer wrote: > > There is more to the thinp metadata than just the metadata superblock. > > The DM thin-pool's metadata device was purposely split out from the data > device to allow for additional metadata fault protection using RAID. > > I'll defer to the LVM developers for if/how LVM can be used to have > thinp metadata redundancy even if you don't have multiple devices to be > able to use a conventional RAID device. > Sure - I'm using thinp on a RAID6 volume, with two disks redundancy. But what about an user error, or a lvm-related bug, which invalidate the superblock? In this case, RAID is of no help. On the other side, a superblock backup copy can be used to restore the system without major data loss. More in general, how do you deal with metadata backups? Thanks. -- Danti Gionatan Supporto Tecnico Assyoma S.r.l. - www.assyoma.it email: g.danti@assyoma.it - info@assyoma.it GPG public key ID: FF5F32A8