From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yh0-f42.google.com ([209.85.213.42]:34233 "EHLO mail-yh0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752563AbbFQLap (ORCPT ); Wed, 17 Jun 2015 07:30:45 -0400 Received: by yhnv31 with SMTP id v31so5346236yhn.1 for ; Wed, 17 Jun 2015 04:30:44 -0700 (PDT) Message-ID: <55815A50.3080309@gmail.com> Date: Wed, 17 Jun 2015 07:30:24 -0400 From: Austin S Hemmelgarn MIME-Version: 1.0 To: Hugo Mills , Arnaud Kapp , linux-btrfs Subject: Re: Replacing a drive from a RAID 1 array References: <20150616165832.GN9850@carfax.org.uk> In-Reply-To: <20150616165832.GN9850@carfax.org.uk> Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha1; boundary="------------ms000500090103090804070906" Sender: linux-btrfs-owner@vger.kernel.org List-ID: This is a cryptographically signed message in MIME format. --------------ms000500090103090804070906 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: quoted-printable On 2015-06-16 12:58, Hugo Mills wrote: > On Tue, Jun 16, 2015 at 06:43:23PM +0200, Arnaud Kapp wrote: >> Hello, >> >> Consider the following situation: I have a RAID 1 array with 4 drives.= >> I want to replace one the drive by a new one, with greater capacity. >> >> However, let's say I only have 4 HDD slots so I cannot plug the new >> drive, add it to the array then remove the other one. >> If there a *safe* way to change drives in this situation? I'd bet that= >> booting with 3drives, adding the new one then removing the old, non >> connected one would work. However, is there something that could go >> wrong in this situation? > > The main thing that could go wrong with that is a disk failure. If > you have the SATA ports available, I'd consider operating the machine > with the case open and one of the drives bare and resting on something > stable and insulating for the time it takes to do a "btrfs replace" > operation. This would be my first suggestion also; although, if you only have 4=20 SATA ports, you might want to invest in a SATA add in card (if you go=20 this way, look for one with an ASmedia chipset, those are the best I've=20 seen as far as reliability for add on controllers). > > If that's not an option, then a good-quality external USB case with= > a short cable directly attached to one of the USB ports on the > motherboard would be a reasonable solution (with the proviso that some > USB connections are just plain unstable and throw errors, which can > cause problems with the filesystem code, typically requiring a reboot, > and a restart of the process). If you decide to go with this option and are using an Intel system,=20 avoid using USB3.0 ports, as a number of Intel's chipsets have known=20 bugs with their USB3 hardware that will likely cause serious issues. If your system has an eSATA port however, try to use that instead of=20 USB, it will almost certainly be faster and more reliable. > > You might also consider using either NBD or iSCSI to present one of= > the disks (I'd probably use the outgoing one) over the network from > another machine with more slots in it, but that's going to end up with > horrible performance during the migration. The other possibility WRT this is ATAoE, which generally gets better=20 performance than NBD or iSCSI but has the caveat that both systems have=20 to be on the same network link (ie, no gateways between them). If you=20 do decide to use ATAoE< look into a program called 'vblade' (most=20 distro's have it in a package with the same name). --------------ms000500090103090804070906 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIIGuDCC BrQwggScoAMCAQICAxBuVTANBgkqhkiG9w0BAQ0FADB5MRAwDgYDVQQKEwdSb290IENBMR4w HAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMTGUNBIENlcnQgU2lnbmlu ZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRAY2FjZXJ0Lm9yZzAeFw0xNTAz MjUxOTM0MzhaFw0xNTA5MjExOTM0MzhaMGMxGDAWBgNVBAMTD0NBY2VydCBXb1QgVXNlcjEj MCEGCSqGSIb3DQEJARYUYWhmZXJyb2luN0BnbWFpbC5jb20xIjAgBgkqhkiG9w0BCQEWE2Fo ZW1tZWxnQG9oaW9ndC5jb20wggIiMA0GCSqGSIb3DQEBAQUAA4ICDwAwggIKAoICAQCdD/zW 2rRAFCLnDfXpWxU1+ODqRVUgzHvrRO7ADUxRo1CBDc3JSX5TIW2OGmQ3DAKGOACp8Z0sgxMc B05tzAZ/M7m4jajVrwwdVCdrwVGxTdAai7Kwg4ZCVfyMVhcwo8R2eW3QahBx34G0RKumK9sZ ZQSQ+zULAzpY6uz7T1sAk/erMoivRXF6u8WvOsLkOD1F/Xyv1ZccSUG5YeDgZgc0nZUBvyIp zXSHjgWerFkrxEM3y2z/Ff3eL1sgGYecV/I1F+I5S01V7Kclt/qRW10c/4JEGRcI1FmrJBPu BtMYPbg/3Y9LZROYN+mVIFxZxOfrmjfFZ96xt/TaMXo8vcEKtWcNEjhGBjEbfMUEm4aq8ygQ 4MuEcpJc8DJCHBkg2KBk13DkbU2qNepTD6Uip1C+g+KMr0nd6KOJqSH27ZuNY4xqV4hIxFHp ex0zY7mq6fV2o6sKBGQzRdI20FDYmNjsLJwjH6qJ8laxFphZnPRpBThmu0AjuBWE72GnI1oA aO+bs92MQGJernt7hByCnDO82W/ykbVz+Ge3Sax8NY0m2Xdvp6WFDY/PjD9CdaJ9nwQGsUSa N54lrZ2qMTeCI9Vauwf6U69BA42xgk65VvxvTNqji+tZ4aZbarZ7el2/QDHOb/rRwlCFplS/ z4l1f1nOrE6bnDl5RBJyW3zi74P6GwIDAQABo4IBWTCCAVUwDAYDVR0TAQH/BAIwADBWBglg hkgBhvhCAQ0ESRZHVG8gZ2V0IHlvdXIgb3duIGNlcnRpZmljYXRlIGZvciBGUkVFIGhlYWQg b3ZlciB0byBodHRwOi8vd3d3LkNBY2VydC5vcmcwDgYDVR0PAQH/BAQDAgOoMEAGA1UdJQQ5 MDcGCCsGAQUFBwMEBggrBgEFBQcDAgYKKwYBBAGCNwoDBAYKKwYBBAGCNwoDAwYJYIZIAYb4 QgQBMDIGCCsGAQUFBwEBBCYwJDAiBggrBgEFBQcwAYYWaHR0cDovL29jc3AuY2FjZXJ0Lm9y ZzAxBgNVHR8EKjAoMCagJKAihiBodHRwOi8vY3JsLmNhY2VydC5vcmcvcmV2b2tlLmNybDA0 BgNVHREELTArgRRhaGZlcnJvaW43QGdtYWlsLmNvbYETYWhlbW1lbGdAb2hpb2d0LmNvbTAN BgkqhkiG9w0BAQ0FAAOCAgEAGvl7xb42JMRH5D/vCIDYvFY3dR2FPd5kmOqpKU/fvQ8ovmJa p5N/FDrsCL+YdslxPY+AAn78PYmL5pFHTdRadT++07DPIMtQyy2qd+XRmz6zP8Il7vGcEDmO WmMLYMq4xV9s/N7t7JJp6ftdIYUcoTVChUgilDaRWMLidtslCdRsBVfUjPb1bF5Ua31diKDP e0M9/e2CU36rbcTtiNCXhptMigzuL3zJXUf2B9jyUV8pnqNEQH36fqJ7YTBLcpq3aYa2XbAH Hgx9GehJBIqwspDmhPCFZ/QmqUXCkt+XfvinQ2NzKR6P3+OdYbwqzVX8BdMeojh7Ig8x/nIx mQ+/ufstL1ZYp0bg13fyK/hPYSIBpayaC76vzWovkIm70DIDRIFLi20p/qTd7rfDYy831Hjm +lDdCECF9bIXEWFk33kA97dgQIMbf5chEmlFg8S0e4iw7LMjvRqMX3eCD8GJ2+oqyZUwzZxy S0Mx+rBld5rrN7LsXwZ671HsGqNeYbYeU25e7t7/Gcc6Bd/kPfA+adEuUGFcvUKH3trDYqNq 6mOkAd8WO/mQadlc3ztS++XDMhmIpfBre9MPAr6usqf+wc+R8Nk9KLK39kEgrqVfzc/fgf8L MaD4rHnusdg4gca6Yi+kNrm99anw7SwaBrBvULYBp7ixNRUhaYiNW4YjTrYxggShMIIEnQIB ATCBgDB5MRAwDgYDVQQKEwdSb290IENBMR4wHAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5v cmcxIjAgBgNVBAMTGUNBIENlcnQgU2lnbmluZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEW EnN1cHBvcnRAY2FjZXJ0Lm9yZwIDEG5VMAkGBSsOAwIaBQCgggH1MBgGCSqGSIb3DQEJAzEL BgkqhkiG9w0BBwEwHAYJKoZIhvcNAQkFMQ8XDTE1MDYxNzExMzAyNFowIwYJKoZIhvcNAQkE MRYEFKpMDpFkadIDIL3dJahd911hhyYkMGwGCSqGSIb3DQEJDzFfMF0wCwYJYIZIAWUDBAEq MAsGCWCGSAFlAwQBAjAKBggqhkiG9w0DBzAOBggqhkiG9w0DAgICAIAwDQYIKoZIhvcNAwIC AUAwBwYFKw4DAgcwDQYIKoZIhvcNAwICASgwgZEGCSsGAQQBgjcQBDGBgzCBgDB5MRAwDgYD VQQKEwdSb290IENBMR4wHAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMT GUNBIENlcnQgU2lnbmluZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRAY2Fj ZXJ0Lm9yZwIDEG5VMIGTBgsqhkiG9w0BCRACCzGBg6CBgDB5MRAwDgYDVQQKEwdSb290IENB MR4wHAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMTGUNBIENlcnQgU2ln bmluZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRAY2FjZXJ0Lm9yZwIDEG5V MA0GCSqGSIb3DQEBAQUABIICADU4Zwv28NFzyAin3eBYbru5LKHcoyrOeSNANQUSlvPoymKN JTx6oEEEdn7lmfwN51Lzr7N9k4I3G4WMXRubFyj7WCFXAOy/zUBlAigKcg+DUoABWNuPRM/H W9UHRm+BAxpsZhJbmDt1KyFINj/KY8YfCzGbcm2K+zyDN+Ll5snYFpHxBvcKqtjs0vKBEnNl eseQqWGE65PDiGiXK4wvV5HhwDsucdT5u+zjNts/COIEAe6rSjcakW+J3+Cx5rvSJbZwQG/G /cflE7u9DiMDxAsrRQUS0ohz0qHAEMvvNoXd0UsMiqI9Fzt9gXxGTUj07zy29yTDXH9rwYy6 O3Hkf8Mtr1EyQQQwqOqJXxSNdW2j2FefeJ52d7ZvnxB1wmqcCvI7KB0T4ZybPI3xMw3AF8fQ feIyHWQw1xg0z5nrTKw18ZH39bh0HgJrvHvgD9W7Do403xkSorpFZIrGrx8SCO+CwvoVOgOA 5FKfm3iuMFbfnoKnHdTC0VzM+eF4GNuRx9SfShWNPswtBj152OGIMpwZgqQfuhgw7hdPxJLM cGiiNZECyKhdKyJIXlAk5LQcZQO3ZWTA3hSt5BaW+l3Srz12xL23MqCOouUs5e1k8AykdmOi 15oTt9bZwePjgS6DoRTJg/lOg/WJV2UYhtLunDfAqesjKb5OU4BOrdzFMUE0AAAAAAAA --------------ms000500090103090804070906--