From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f177.google.com ([209.85.213.177]:35548 "EHLO mail-ig0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964863AbbLGPj0 (ORCPT ); Mon, 7 Dec 2015 10:39:26 -0500 Received: by igl9 with SMTP id 9so76385231igl.0 for ; Mon, 07 Dec 2015 07:39:25 -0800 (PST) Subject: Re: Scrub on btrfs single device only to detect errors, not correct them? To: Jon Panozzo References: <56659F48.6000800@gmail.com> Cc: Duncan <1i5t5.duncan@cox.net>, Btrfs BTRFS From: Austin S Hemmelgarn Message-ID: <5665A819.9030804@gmail.com> Date: Mon, 7 Dec 2015 10:39:05 -0500 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha-512; boundary="------------ms030507010400050102010807" Sender: linux-btrfs-owner@vger.kernel.org List-ID: This is a cryptographically signed message in MIME format. --------------ms030507010400050102010807 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable On 2015-12-07 10:12, Jon Panozzo wrote: > This is what I was thinking as well. In my particular use-case, > parity is only really used today to reconstruct an entire device due > to a device failure. I think if btrfs scrub detected errors on a > single device, I could do a "reverse reconstruct" where instead of > syncing TO the parity disk, I sync FROM the parity disk TO the btrfs > single device with the error, replacing physical blocks that are out > of sync with parity (thus repairing the scrub-found errrors). The > downside to this approach is I would have to perform the reverse-sync > against the entire btrfs block device, which could be much more > time-consuming than if I could single out the specific block addresses > and just sync those. That said, I guess option A is better than no > option at all. > > I would be curious if any of the devs or other members of this mailing > list have tried to correlate btrfs internal block addresses to a true > block-address on the device being used. Any interesting articles / > links that show how to do this? Not expecting much, but if someone > does know, I'd be very grateful. I think there is a tool in btrfs-progs to do it, but I've never used it, = and you would still need to get scrub to spit out actual error addresses = for you. --------------ms030507010400050102010807 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 Brgwgga0MIIEnKADAgECAgMRLfgwDQYJKoZIhvcNAQENBQAweTEQMA4GA1UEChMHUm9vdCBD QTEeMBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0IFNp Z25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2VydC5vcmcwHhcN MTUwOTIxMTEzNTEzWhcNMTYwMzE5MTEzNTEzWjBjMRgwFgYDVQQDEw9DQWNlcnQgV29UIFVz 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 b20wDQYJKoZIhvcNAQENBQADggIBADMnxtSLiIunh/TQcjnRdf63yf2D8jMtYUm4yDoCF++J jCXbPQBGrpCEHztlNSGIkF3PH7ohKZvlqF4XePWxpY9dkr/pNyCF1PRkwxUURqvuHXbu8Lwn 8D3U2HeOEU3KmrfEo65DcbanJCMTTW7+mU9lZICPP7ZA9/zB+L0Gm1UNFZ6AU50N/86vjQfY WgkCd6dZD4rQ5y8L+d/lRbJW7ZGEQw1bSFVTRpkxxDTOwXH4/GpQfnfqTAtQuJ1CsKT12e+H NSD/RUWGTr289dA3P4nunBlz7qfvKamxPymHeBEUcuICKkL9/OZrnuYnGROFwcdvfjGE5iLB kjp/ttrY4aaVW5EsLASNgiRmA6mbgEAMlw3RwVx0sVelbiIAJg9Twzk4Ct6U9uBKiJ8S0sS2 8RCSyTmCRhJs0vvva5W9QUFGmp5kyFQEoSfBRJlbZfGX2ehI2Hi3U2/PMUm2ONuQG1E+a0AP u7I0NJc/Xil7rqR0gdbfkbWp0a+8dAvaM6J00aIcNo+HkcQkUgtfrw+C2Oyl3q8IjivGXZqT 5UdGUb2KujLjqjG91Dun3/RJ/qgQlotH7WkVBs7YJVTCxfkdN36rToPcnMYOI30FWa0Q06gn F6gUv9/mo6riv3A5bem/BdbgaJoPnWQD9D8wSyci9G4LKC+HQAMdLmGoeZfpJzKHMYIE0TCC BM0CAQEwgYAweTEQMA4GA1UEChMHUm9vdCBDQTEeMBwGA1UECxMVaHR0cDovL3d3dy5jYWNl cnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0IFNpZ25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcN AQkBFhJzdXBwb3J0QGNhY2VydC5vcmcCAxEt+DANBglghkgBZQMEAgMFAKCCAiEwGAYJKoZI hvcNAQkDMQsGCSqGSIb3DQEHATAcBgkqhkiG9w0BCQUxDxcNMTUxMjA3MTUzOTA1WjBPBgkq hkiG9w0BCQQxQgRA4h33FI2WhwPasKHK0P54N5QYGiiy2psNRXpnv69sBZg2bCSBdsGzyv10 RSMDDSL4ND0gQS4f/nxkaaVk/DOktDBsBgkqhkiG9w0BCQ8xXzBdMAsGCWCGSAFlAwQBKjAL BglghkgBZQMEAQIwCgYIKoZIhvcNAwcwDgYIKoZIhvcNAwICAgCAMA0GCCqGSIb3DQMCAgFA MAcGBSsOAwIHMA0GCCqGSIb3DQMCAgEoMIGRBgkrBgEEAYI3EAQxgYMwgYAweTEQMA4GA1UE ChMHUm9vdCBDQTEeMBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlD QSBDZXJ0IFNpZ25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2Vy dC5vcmcCAxEt+DCBkwYLKoZIhvcNAQkQAgsxgYOggYAweTEQMA4GA1UEChMHUm9vdCBDQTEe MBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0IFNpZ25p bmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2VydC5vcmcCAxEt+DAN BgkqhkiG9w0BAQEFAASCAgCOcF0RJRhyt3ecifl95ms9JtlLgA9spUqRzH7EKrBBT9UG+Djp JIkNYvf7fNhGZVY2TB5AtOVeHupAqNKIHOGJDHnZyOTryz8us2goLr/hXN+vdj/lYT12bdnU aN2zhg3gYVdz8lblXzVy5sjrWjsFmGiykFsJsBs0nk2/rCLpm3B1sgEeBhTGG+t6uxHaIZo0 TJO45XS9rLm0qyE/u2+FjcbwdX0lBkby5Ej+rv/WSwV3aViSvLrlI6Az8oGIT/in37PJfbJh T3OADP08uTPIMKd6mzYUcaJpZZDtDZbKR76L5CLIHZU+EPUGLsE1Z8of5gp2+oTVmCDQ2VSr bUM6/UWPHehC4pVE0iq7Vrc2AMoi+mg1u9XE0uOQg7GBnscEPlq6vsby6GFZqcuDEtMCWw1g FZGSHzKMV64oxBHAzV81+24aypv457TwRpni64PXUXYqf4fayh6Lx2ZVObgAIW+Vi9ju8V5H he/FFbbQDLE5IeK69W8wkGqYFXW/KcjjhCcBuamOmReUu/ATLl3Lcd3PSD4T6PdOSnSsxOhS Wg5YkOtup8+Xo9iZqylbg4ZL+jSQNc4RaO/DutXekxkbtfry+3lU5b1jVSidY1b3BwqBQjKu 1VjCpnIJUZ24J4dUgP1I7IGBlJJ3Ulon03UE12bzIch2DQcnk5gn+FlfYAAAAAAAAA== --------------ms030507010400050102010807--