From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f182.google.com ([209.85.213.182]:33179 "EHLO mail-ig0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751068AbbIRN3v (ORCPT ); Fri, 18 Sep 2015 09:29:51 -0400 Received: by igbkq10 with SMTP id kq10so35613936igb.0 for ; Fri, 18 Sep 2015 06:29:50 -0700 (PDT) Subject: Re: RAID1 storage server won't boot with one disk missing To: Chris Murphy , Roman Mamedov References: <55FAD9CC.5060206@oracle.com> <55FAF198.2060106@libero.it> <20150918000205.6e8f3998@natsu> Cc: Btrfs BTRFS From: Austin S Hemmelgarn Message-ID: <55FC11C4.60506@gmail.com> Date: Fri, 18 Sep 2015 09:29:40 -0400 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha-512; boundary="------------ms030007080401000505060808" Sender: linux-btrfs-owner@vger.kernel.org List-ID: This is a cryptographically signed message in MIME format. --------------ms030007080401000505060808 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable On 2015-09-17 16:18, Chris Murphy wrote: > On Thu, Sep 17, 2015 at 1:02 PM, Roman Mamedov wrote: >> On Thu, 17 Sep 2015 19:00:08 +0200 >> Goffredo Baroncelli wrote: >> >>> On 2015-09-17 17:18, Anand Jain wrote: >>>> it looks like -o degraded is going to be a very obvious feature, >>>> I have plans of making it a default feature, and provide -o >>>> nodegraded feature instead. Thanks for comments if any. >>>> >>> I am not sure if there is a "good" default for this kind of problem >> >> Yes there is. It is whatever people came to expect from using other RA= ID >> systems and/or generally expect from RAID as a concept. >> >> Both mdadm software RAID, and I believe virtually any hardware RAID co= ntroller >> out there will let you to successfully boot up and give read-write(!) = access >> to a RAID in a non-critical failure state, because that's kind of the = whole >> point of a RAID, to eliminate downtime. If the removed disk is later r= e-added, >> then it is automatically resynced. Mdadm can also make use of its 'wri= te >> intent bitmap' to resync only those areas of the array which were in a= ny way >> touched during the absence of the newly re-added disk. >> >> If you're concerned that the user "misses" the fact that they have a d= isk >> down, then solve *that*, make some sort of a notify daemon, e.g. mdadm= has a >> built-in "monitor" mode which sends E-Mail on critical events with any= of the >> arrays. > > Given the current state: no proposal and no work done yet, I think > it's premature to change the default. > > It's an open question what a modern monitoring and notification > mechanism should look like. At the moment it'd be a unique Btrfs thing > because the mdadm and LVM methods aren't abstracted enough to reuse. I > wonder if the storaged and/or openlmi folks have some input on what > this would look like. Feedback from KDE and GNOME also, who rely on at > least mdadm in order to present user space notifications. I think > udisks2 is on the way out and storaged is on the way in, there's just > too much stuff that udisks2 doesn't do and is getting confused about, > including LVM thinly provisioned volumes, not just Btrfs stuff. > > The problem with that is that storaged (from what I understand) is=20 systemd dependent, and there are too many people out there who don't=20 want systemd. udisks2 will almost certainly live on (just like=20 consolekit has). And if it's something systemd integrated, I can=20 already tell you it will look like the OS X solution. Now, what I think = it should look like is a different story, I'd say that: 1. It should give the option to either: a. Refuse to boot degraded. b. Ask the operator if he wants to boot degraded c. Just automatically boot degraded, and probably send a=20 notification about it. 2. Provide some service (sadly probably dbus based) to schedule=20 scrub/balance/re-sync operations and get info about ENOSPC/sync=20 failure/parity mismatch/device failure/SMART status failure. 3. Provide a consistent interface to such operations on hardware RAID=20 controllers that support them. 4. Provide the ability to notify via arbitrary means on any of the above = mentioned issues. 5. Have the ability to turn anything not needed off on a given system. --------------ms030007080401000505060808 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 hvcNAQkDMQsGCSqGSIb3DQEHATAcBgkqhkiG9w0BCQUxDxcNMTUwOTE4MTMyOTQwWjBPBgkq hkiG9w0BCQQxQgRAqMteNDupid+g7wHJI8ndX7U6A239SDVyt+Nizi0u9ldKC3HO4BH95iV5 pzaCI5wB10hjsozzjBHDqgt9GnY/lzBsBgkqhkiG9w0BCQ8xXzBdMAsGCWCGSAFlAwQBKjAL BglghkgBZQMEAQIwCgYIKoZIhvcNAwcwDgYIKoZIhvcNAwICAgCAMA0GCCqGSIb3DQMCAgFA MAcGBSsOAwIHMA0GCCqGSIb3DQMCAgEoMIGRBgkrBgEEAYI3EAQxgYMwgYAweTEQMA4GA1UE ChMHUm9vdCBDQTEeMBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlD QSBDZXJ0IFNpZ25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2Vy dC5vcmcCAxBuVTCBkwYLKoZIhvcNAQkQAgsxgYOggYAweTEQMA4GA1UEChMHUm9vdCBDQTEe MBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0IFNpZ25p bmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2VydC5vcmcCAxBuVTAN BgkqhkiG9w0BAQEFAASCAgBu7JOkWj+vb1pbNoOD9/nD9DRciYF4ULSZEN9lnfr5PPetdPXF BagGtXICQoqYQKALX9R432t2R2EanzqWnRJjP7cE7lRKhyj0cq9vni1p2dB6RMBA41oLM1dV EXDjSZG46kGNXUdAq+aQjVW3zENZSHmx+IuCfHjc58w+YZ5f2s93PWBEQS2jXbfYpHWb4c5n c9mxxDS/n+i3DY/UNVsq8nJrvZZ2gaFx66Zcm+ghDfbKqF5zjuboLTg39mY+NF62wetv6930 5TllOKnVWXoUxLE1nNfss86jT3cVyvBteaH9cCe2sOp8o1HaLfwSv4AWoYWpcShd6JvOEFdx sxKtAfhiGsdiKqhmWfZdBw17HlEJo0TU8hR2RrZAtwlGVn1EOCVCM6E3zoSeeGPDLwNb4WoO hHfewdpkknHD73GIMNXVaXh+KK22zpsRAWLKT1q8TMNKqowTTQV3rrVC6DWGb0K0Dji2DOD/ fzCizCCKvx3oo5EBdDDbmME+65SMBLlwI/NUyEDCXHL4nGq36zf969IXbzZoeR97IF2qGJTq 6VF3TrSRdjRNyn6UekqzOGxmYQIz9ivQKwA4yT6AS24k+hQgaIXUgC27heiYThAFYkRe19uL KKWlCkJIlmppHGHOWXfS48mLNatlrDnn1v7Lb3my7Fd1C//WzJVvLTP3QQAAAAAAAA== --------------ms030007080401000505060808--