From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dennis Schridde Date: Wed, 23 May 2018 21:39:47 +0200 Message-ID: <7415801.S7CYg4Nbn9@monk> In-Reply-To: <254418594.lCqEE9x6Ep@monk> References: <1973783.dFIIZJkBNM@monk> <254418594.lCqEE9x6Ep@monk> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart1653596.EixhxDBoGf"; micalg="pgp-sha256"; protocol="application/pgp-signature" Subject: Re: [linux-lvm] Check of pool ernie/cache failed (status:1). Manual repair required! 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: To: linux-lvm@redhat.com Cc: Zdenek Kabelac --nextPart1653596.EixhxDBoGf Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" On Wednesday, 16 May 2018 20:31:15 CEST Dennis Schridde wrote: > On Tuesday, 15 May 2018 13:15:55 CEST Zdenek Kabelac wrote: > > Dne 15.5.2018 v 10:11 Dennis Schridde napsal(a): > > To get direct access to metadata - you could use your latest lvm2 2.02.177 > > build (or even 'git master'). In these recent versions there is added > > support to activate directly these 'subLVs'. So with latest lvm2 you can: > > > > lvchange -ay vg/lv_cmeta > > I tried that (using 2.02.177), but it does not work: > # lvchange -ay ernie/cache_cmeta > Operation not permitted on hidden LV ernie/cache_cmeta. Does anyone have a suggestion how I can activate this volume in order to extract the information Zdenek asked for? For more context please see the start of this thread. The gist is that my cached LV cannot be activated anymore, and `lvconvert --repair` reports: bad checksum in superblock Repair of cache metadata volume of cache ernie/system failed (status:1). Manual repair required! My most important questions are: * What is broken? - What information does the superblock carry / what is its purpose? - Where is it located / which part of my disk was damaged? - What will be the consequence of it being irrecoverably lost? * What does "manual repair" mean in detail? - Using a specific tool? - Flipping bits using a hex editor? * Is there some way to recover the cache? Or is it at least possible to uncache the LV forcibly, to hopefully recover the data on the origin LV? * What is your recommendation to minimise data loss? --Dennis --nextPart1653596.EixhxDBoGf Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part. Content-Transfer-Encoding: 7Bit -----BEGIN PGP SIGNATURE----- iQGzBAABCAAdFiEE0Ngi/nirHnbsz3NFz+h/M161qdwFAlsFw4MACgkQz+h/M161 qdxqpwwAkGQv0p8Ofk5/w3Oxl7iRK9PtBXLUomiR7P19hS6le5j05qXjs3t6W0zn Wzvb98g4+WQD/7ivuqghBbJiFGk4uke+8q5mpjkPYJMnMurbmRzHvYzyACugobz0 CwKcCNCeJ2yJaMXm705ByckuhIBkDBX8cJEJ4vD59X97N3LB2REZpnDWSU0KjqIN 5jSYO79PQOpwCgcgdlNz15cXaEo/1tEreCujAL7TYiKRRpJs4WmtjbotfFXgkzaz vsqwaoo5UKz9pprvpVKScHuK1XKoPrvyjGcWW51DK2f9VqwHstlax5qgmxjpOJ7m NXAK49+SgJWF92WdtUO9D9Ob6sJojYrklmSEZpYeJWRVLFCAGkV9VNz60sOBAq5c 2wxgdxq3Wbrvs5ooZ6K26wJUj5hpu5W8VMJI7ncmQhtN6pJxa00YVnT17EuovkJ+ 3lsdM8fChN0hfrB+P7VtzNfUXY+qSEZcskndJLkILjHTd4EfV13EgvVF9DUGwZPp Ti4NH6Il =Ne2T -----END PGP SIGNATURE----- --nextPart1653596.EixhxDBoGf--