From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f181.google.com ([209.85.223.181]:35134 "EHLO mail-io0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751517AbbHMLoY (ORCPT ); Thu, 13 Aug 2015 07:44:24 -0400 Received: by iodt126 with SMTP id t126so49128481iod.2 for ; Thu, 13 Aug 2015 04:44:24 -0700 (PDT) Subject: Re: RAID0 wrong (raw) device? To: Ulli Horlacher , linux-btrfs@vger.kernel.org References: <20150812130758.GA26529@rus.uni-stuttgart.de> From: Austin S Hemmelgarn Message-ID: <55CC830D.2070304@gmail.com> Date: Thu, 13 Aug 2015 07:44:13 -0400 MIME-Version: 1.0 In-Reply-To: <20150812130758.GA26529@rus.uni-stuttgart.de> Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha-512; boundary="------------ms060405000104050706000102" Sender: linux-btrfs-owner@vger.kernel.org List-ID: This is a cryptographically signed message in MIME format. --------------ms060405000104050706000102 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: quoted-printable A couple of observations: 1. BTRFS currently has no knowledge of multipath or anything like that.=20 In theory it should work fine as long as the multiple device instances = all point to the same storage directly (including having identical block = addresses), but we still need to add proper handling for it. 2. Be _VERY_ careful using BTRFS on top of _ANY_ kind of shared storage. = Most non-clustered filesystems will have issues if multiply mounted,=20 but in almost all cases I've personally seen, it _WILL_ cause=20 irreparable damage to a BTRFS filesystem (we really need to do something = like ext4's MMP in BTRFS). 3. See the warnings about doing block level copies and LVM snapshots of=20 BTRFS volumes, the same applies to using it on DRBD currently as well=20 (with the possible exception of remote DRBD nodes (ie, ones without a=20 local copy of the backing store) (in this case, we need to blacklist=20 backing devices for stacked storage (I think the same issue may be=20 present with BTRFS on a MD based RAID1 set). --------------ms060405000104050706000102 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgMFADCABgkqhkiG9w0BBwEAAKCC Brgwgga0MIIEnKADAgECAgMQblUwDQYJKoZIhvcNAQENBQAweTEQMA4GA1UEChMHUm9vdCBD QTEeMBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0IFNp Z25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2VydC5vcmcwHhcN MTUwMzI1MTkzNDM4WhcNMTUwOTIxMTkzNDM4WjBjMRgwFgYDVQQDEw9DQWNlcnQgV29UIFVz ZXIxIzAhBgkqhkiG9w0BCQEWFGFoZmVycm9pbjdAZ21haWwuY29tMSIwIAYJKoZIhvcNAQkB FhNhaGVtbWVsZ0BvaGlvZ3QuY29tMIICIjANBgkqhkiG9w0BAQEFAAOCAg8AMIICCgKCAgEA nQ/81tq0QBQi5w316VsVNfjg6kVVIMx760TuwA1MUaNQgQ3NyUl+UyFtjhpkNwwChjgAqfGd LIMTHAdObcwGfzO5uI2o1a8MHVQna8FRsU3QGouysIOGQlX8jFYXMKPEdnlt0GoQcd+BtESr pivbGWUEkPs1CwM6WOrs+09bAJP3qzKIr0VxervFrzrC5Dg9Rf18r9WXHElBuWHg4GYHNJ2V Ab8iKc10h44FnqxZK8RDN8ts/xX93i9bIBmHnFfyNRfiOUtNVeynJbf6kVtdHP+CRBkXCNRZ qyQT7gbTGD24P92PS2UTmDfplSBcWcTn65o3xWfesbf02jF6PL3BCrVnDRI4RgYxG3zFBJuG qvMoEODLhHKSXPAyQhwZINigZNdw5G1NqjXqUw+lIqdQvoPijK9J3eijiakh9u2bjWOMaleI SMRR6XsdM2O5qun1dqOrCgRkM0XSNtBQ2JjY7CycIx+qifJWsRaYWZz0aQU4ZrtAI7gVhO9h pyNaAGjvm7PdjEBiXq57e4QcgpwzvNlv8pG1c/hnt0msfDWNJtl3b6elhQ2Pz4w/QnWifZ8E BrFEmjeeJa2dqjE3giPVWrsH+lOvQQONsYJOuVb8b0zao4vrWeGmW2q2e3pdv0Axzm/60cJQ haZUv8+JdX9ZzqxOm5w5eUQSclt84u+D+hsCAwEAAaOCAVkwggFVMAwGA1UdEwEB/wQCMAAw VgYJYIZIAYb4QgENBEkWR1RvIGdldCB5b3VyIG93biBjZXJ0aWZpY2F0ZSBmb3IgRlJFRSBo ZWFkIG92ZXIgdG8gaHR0cDovL3d3dy5DQWNlcnQub3JnMA4GA1UdDwEB/wQEAwIDqDBABgNV HSUEOTA3BggrBgEFBQcDBAYIKwYBBQUHAwIGCisGAQQBgjcKAwQGCisGAQQBgjcKAwMGCWCG SAGG+EIEATAyBggrBgEFBQcBAQQmMCQwIgYIKwYBBQUHMAGGFmh0dHA6Ly9vY3NwLmNhY2Vy dC5vcmcwMQYDVR0fBCowKDAmoCSgIoYgaHR0cDovL2NybC5jYWNlcnQub3JnL3Jldm9rZS5j cmwwNAYDVR0RBC0wK4EUYWhmZXJyb2luN0BnbWFpbC5jb22BE2FoZW1tZWxnQG9oaW9ndC5j b20wDQYJKoZIhvcNAQENBQADggIBABr5e8W+NiTER+Q/7wiA2LxWN3UdhT3eZJjqqSlP370P KL5iWqeTfxQ67Ai/mHbJcT2PgAJ+/D2Ji+aRR03UWnU/vtOwzyDLUMstqnfl0Zs+sz/CJe7x nBA5jlpjC2DKuMVfbPze7eySaen7XSGFHKE1QoVIIpQ2kVjC4nbbJQnUbAVX1Iz29WxeVGt9 XYigz3tDPf3tglN+q23E7YjQl4abTIoM7i98yV1H9gfY8lFfKZ6jREB9+n6ie2EwS3Kat2mG tl2wBx4MfRnoSQSKsLKQ5oTwhWf0JqlFwpLfl374p0Njcykej9/jnWG8Ks1V/AXTHqI4eyIP Mf5yMZkPv7n7LS9WWKdG4Nd38iv4T2EiAaWsmgu+r81qL5CJu9AyA0SBS4ttKf6k3e63w2Mv N9R45vpQ3QhAhfWyFxFhZN95APe3YECDG3+XIRJpRYPEtHuIsOyzI70ajF93gg/BidvqKsmV MM2ccktDMfqwZXea6zey7F8Geu9R7BqjXmG2HlNuXu7e/xnHOgXf5D3wPmnRLlBhXL1Ch97a w2KjaupjpAHfFjv5kGnZXN87UvvlwzIZiKXwa3vTDwK+rrKn/sHPkfDZPSiyt/ZBIK6lX83P 34H/CzGg+Kx57rHYOIHGumIvpDa5vfWp8O0sGgawb1C2Aae4sTUVIWmIjVuGI062MYIE0TCC BM0CAQEwgYAweTEQMA4GA1UEChMHUm9vdCBDQTEeMBwGA1UECxMVaHR0cDovL3d3dy5jYWNl cnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0IFNpZ25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcN AQkBFhJzdXBwb3J0QGNhY2VydC5vcmcCAxBuVTANBglghkgBZQMEAgMFAKCCAiEwGAYJKoZI hvcNAQkDMQsGCSqGSIb3DQEHATAcBgkqhkiG9w0BCQUxDxcNMTUwODEzMTE0NDEzWjBPBgkq hkiG9w0BCQQxQgRArQBl6qEReZqNxcW25BegMiXUiAksvPCDNOx+ACdJ35b2mF5oObkS/OoR toHPy6kECw5y8JF4Dk9R3MjHYxy3KTBsBgkqhkiG9w0BCQ8xXzBdMAsGCWCGSAFlAwQBKjAL BglghkgBZQMEAQIwCgYIKoZIhvcNAwcwDgYIKoZIhvcNAwICAgCAMA0GCCqGSIb3DQMCAgFA MAcGBSsOAwIHMA0GCCqGSIb3DQMCAgEoMIGRBgkrBgEEAYI3EAQxgYMwgYAweTEQMA4GA1UE ChMHUm9vdCBDQTEeMBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlD QSBDZXJ0IFNpZ25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2Vy dC5vcmcCAxBuVTCBkwYLKoZIhvcNAQkQAgsxgYOggYAweTEQMA4GA1UEChMHUm9vdCBDQTEe MBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0IFNpZ25p bmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2VydC5vcmcCAxBuVTAN BgkqhkiG9w0BAQEFAASCAgBgNNJ0I+F5dRsFCNjPPYy+aX1SJjOJVMI5VQ51nfwdNncrJp9V Vj9/Cwm22vpjfImAgryV4j8vEBhDQWG4L/2MkOP/fA+GKCSAhxI08VwEp6tHb9Wr/tqMm8wp iQhZOdB43/ce4wAhORT8lCPwMBoqVNWIhOiwv7O/wALpOFi+u7YJ/VLX/aBkmh5MlSoUrxnd pAAuKXQtHcXsNYvWjXER+oty1BVxSOiVxYnPaQv0UyKoaEFOr4rVskGiLy30nO1xGY7+CzYw bl8iU/j6urRtwg9ZT9s/Eka5N3G/KOgsbSX9wCmn77REHRF7jWcafgWTUhv4M16j0vMlTA6n gLRp4e2X4B8zN2+WApwy/TXSFs/YedIPm8U3T3YhC1FFnZJoDt3/CfhG1bMbb65WEEmm9C6D /RLZPR7xhzpFVWQNVtsAB6rFAbNuMlQz4dqGW7vfP+YY0tJdjZJLXd77WbFKQFzLW3QfK1GK 6vDBRAqIDZ4mGXRyrra2j9m5g/HpcAWHi1qH2M5KAFFcxjCBz+5HGAptCbNAgpGsoalgmO23 md06F24kmZ3WUBPVKXPnUSwhCELloIyppBQ4k3AWdrWwBRsr13b18heecozu4RjkEOm8XcYQ S8zvbIvtwHnHO+DXO/n4DZysz8h5NsdwQ5StlCZTS+ZzlMgoiRTCm28h7QAAAAAAAA== --------------ms060405000104050706000102--