Date: Thu, 11 Sep 2014 08:30:22 -0500 From: Karl Denninger <karl@denninger.net> To: freebsd-stable@freebsd.org Subject: Re: getting to 4K disk blocks in ZFS Message-ID: <5411A3EE.4040202@denninger.net> In-Reply-To: <E1XS0KJ-000Hhc-Lu@dilbert.ingresso.co.uk> References: <540FF3C4.6010305@ish.com.au> <54100258.2000505@freebsd.org> <E1XS0KJ-000Hhc-Lu@dilbert.ingresso.co.uk>
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This is a cryptographically signed message in MIME format. --------------ms030001000802070007020408 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: quoted-printable On 9/11/2014 4:06 AM, Pete French wrote: >> This may never hit you, but ZFS is built on the assumption, that it >> cannot happen at all, which is no longer true with 4KB drives that >> are used with ashift=3D9. > Have just been reading this thread, and as people are suggesting > moving ashift from 9 to 12, doesnt using use 512B drives with > ahift=3D12 also violate this ? Or is it smart enough ot know that > the underlying sectors are separate ? > No, because in order for the "write" (as ZFS sees it) to succeed all of=20 them must succeed. The problem comes when the *drive* (or controller) does a=20 read-replace-write, because ZFS is unaware of the underlying act and=20 "silent" corruption can thus (at least theoretically) happen. --=20 Karl Denninger karl@denninger.net <mailto:karl@denninger.net> /The Market Ticker/ --------------ms030001000802070007020408 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIIFTzCC BUswggQzoAMCAQICAQgwDQYJKoZIhvcNAQEFBQAwgZ0xCzAJBgNVBAYTAlVTMRAwDgYDVQQI EwdGbG9yaWRhMRIwEAYDVQQHEwlOaWNldmlsbGUxGTAXBgNVBAoTEEN1ZGEgU3lzdGVtcyBM TEMxHDAaBgNVBAMTE0N1ZGEgU3lzdGVtcyBMTEMgQ0ExLzAtBgkqhkiG9w0BCQEWIGN1c3Rv bWVyLXNlcnZpY2VAY3VkYXN5c3RlbXMubmV0MB4XDTEzMDgyNDE5MDM0NFoXDTE4MDgyMzE5 MDM0NFowWzELMAkGA1UEBhMCVVMxEDAOBgNVBAgTB0Zsb3JpZGExFzAVBgNVBAMTDkthcmwg RGVubmluZ2VyMSEwHwYJKoZIhvcNAQkBFhJrYXJsQGRlbm5pbmdlci5uZXQwggIiMA0GCSqG SIb3DQEBAQUAA4ICDwAwggIKAoICAQC5n2KBrBmG22nVntVdvgKCB9UcnapNThrW1L+dq6th d9l4mj+qYMUpJ+8I0rTbY1dn21IXQBoBQmy8t1doKwmTdQ59F0FwZEPt/fGbRgBKVt3Quf6W 6n7kRk9MG6gdD7V9vPpFV41e+5MWYtqGWY3ScDP8SyYLjL/Xgr+5KFKkDfuubK8DeNqdLniV jHo/vqmIgO+6NgzPGPgmbutzFQXlxUqjiNAAKzF2+Tkddi+WKABrcc/EqnBb0X8GdqcIamO5 SyVmuM+7Zdns7D9pcV16zMMQ8LfNFQCDvbCuuQKMDg2F22x5ekYXpwjqTyfjcHBkWC8vFNoY 5aFMdyiN/Kkz0/kduP2ekYOgkRqcShfLEcG9SQ4LQZgqjMpTjSOGzBr3tOvVn5LkSJSHW2Z8 Q0dxSkvFG2/lsOWFbwQeeZSaBi5vRZCYCOf5tRd1+E93FyQfpt4vsrXshIAk7IK7f0qXvxP4 GDli5PKIEubD2Bn+gp3vB/DkfKySh5NBHVB+OPCoXRUWBkQxme65wBO02OZZt0k8Iq0i4Rci WV6z+lQHqDKtaVGgMsHn6PoeYhjf5Al5SP+U3imTjF2aCca1iDB5JOccX04MNljvifXgcbJN nkMgrzmm1ZgJ1PLur/ADWPlnz45quOhHg1TfUCLfI/DzgG7Z6u+oy4siQuFr9QT0MQIDAQAB o4HWMIHTMAkGA1UdEwQCMAAwEQYJYIZIAYb4QgEBBAQDAgWgMAsGA1UdDwQEAwIF4DAsBglg hkgBhvhCAQ0EHxYdT3BlblNTTCBHZW5lcmF0ZWQgQ2VydGlmaWNhdGUwHQYDVR0OBBYEFHw4 +LnuALyLA5Cgy7T5ZAX1WzKPMB8GA1UdIwQYMBaAFF3U3hpBZq40HB5VM7B44/gmXiI0MDgG CWCGSAGG+EIBAwQrFilodHRwczovL2N1ZGFzeXN0ZW1zLm5ldDoxMTQ0My9yZXZva2VkLmNy bDANBgkqhkiG9w0BAQUFAAOCAQEAZ0L4tQbBd0hd4wuw/YVqEBDDXJ54q2AoqQAmsOlnoxLO 31ehM/LvrTIP4yK2u1VmXtUumQ4Ao15JFM+xmwqtEGsh70RRrfVBAGd7KOZ3GB39FP2TgN/c L5fJKVxOqvEnW6cL9QtvUlcM3hXg8kDv60OB+LIcSE/P3/s+0tEpWPjxm3LHVE7JmPbZIcJ1 YMoZvHh0NSjY5D0HZlwtbDO7pDz9sZf1QEOgjH828fhtborkaHaUI46pmrMjiBnY6ujXMcWD pxtikki0zY22nrxfTs5xDWGxyrc/cmucjxClJF6+OYVUSaZhiiHfa9Pr+41okLgsRB0AmNwE f6ItY3TI8DGCBQowggUGAgEBMIGjMIGdMQswCQYDVQQGEwJVUzEQMA4GA1UECBMHRmxvcmlk YTESMBAGA1UEBxMJTmljZXZpbGxlMRkwFwYDVQQKExBDdWRhIFN5c3RlbXMgTExDMRwwGgYD VQQDExNDdWRhIFN5c3RlbXMgTExDIENBMS8wLQYJKoZIhvcNAQkBFiBjdXN0b21lci1zZXJ2 aWNlQGN1ZGFzeXN0ZW1zLm5ldAIBCDAJBgUrDgMCGgUAoIICOzAYBgkqhkiG9w0BCQMxCwYJ KoZIhvcNAQcBMBwGCSqGSIb3DQEJBTEPFw0xNDA5MTExMzMwMjJaMCMGCSqGSIb3DQEJBDEW BBQQUUg8MuFmGWyQzjUqaT5vcMEiKjBsBgkqhkiG9w0BCQ8xXzBdMAsGCWCGSAFlAwQBKjAL BglghkgBZQMEAQIwCgYIKoZIhvcNAwcwDgYIKoZIhvcNAwICAgCAMA0GCCqGSIb3DQMCAgFA MAcGBSsOAwIHMA0GCCqGSIb3DQMCAgEoMIG0BgkrBgEEAYI3EAQxgaYwgaMwgZ0xCzAJBgNV BAYTAlVTMRAwDgYDVQQIEwdGbG9yaWRhMRIwEAYDVQQHEwlOaWNldmlsbGUxGTAXBgNVBAoT EEN1ZGEgU3lzdGVtcyBMTEMxHDAaBgNVBAMTE0N1ZGEgU3lzdGVtcyBMTEMgQ0ExLzAtBgkq hkiG9w0BCQEWIGN1c3RvbWVyLXNlcnZpY2VAY3VkYXN5c3RlbXMubmV0AgEIMIG2BgsqhkiG 9w0BCRACCzGBpqCBozCBnTELMAkGA1UEBhMCVVMxEDAOBgNVBAgTB0Zsb3JpZGExEjAQBgNV BAcTCU5pY2V2aWxsZTEZMBcGA1UEChMQQ3VkYSBTeXN0ZW1zIExMQzEcMBoGA1UEAxMTQ3Vk YSBTeXN0ZW1zIExMQyBDQTEvMC0GCSqGSIb3DQEJARYgY3VzdG9tZXItc2VydmljZUBjdWRh c3lzdGVtcy5uZXQCAQgwDQYJKoZIhvcNAQEBBQAEggIAPFTlvZyoC5rTy3uOgywknoe7+nzT kh7E3y1tY1j5EWlehsggWCsYaclRrSgGKAlsxjaAmFm2Kz+CruhncHS0ZUTDPjObUUdM8fsj urX94zIAE3ugRNKP3d+KVUv1GB9KG7NBSH/WfgiCXwmgFjf1koyNIEgeLTme5AYiYj+ALcfd b3sQaddqnMJMk4Ko/NMQh0zikkRB9w1CaSERHWyLH2gY8P0NJXP9sCPKId4gANf2FiMeDhzU K98/gMKhCHsngXauetCTDbGZQRuQJfsTS2fqPqfyJwez5yU0aZRE5wUp8LJQuqtXyCcwbKtI mCNogi77teBYkDq4mnRXmR9l2GFpRynG4VUBjQ8fb9eoPuYolj1a/GleD2taTi8nrrWI3VSS 5S38dSPKlIgDDmpcxmfQgwoGcEEZg7kyIcCg/Yg2pTndcZtXvnhU8ZObxV8uywCxcbj0K4VD CzswW+93eA/3FcYeNj/Az2iIIJUcoutKZedujk5e58C4RDn5m5eBtFRcMGMeqSs7nnB4CVwn HF708wjKE9WiFWBYZgkTOWBtZJaIhIfPdpmcDKL2DfojbU3NxtYN1FZm0FU0FcKtAQcigJS/ 2RWmYP/5/mwCcXsbHBPpRKIoLnWhNy3PKEL65IWCbleKYljHMtzSccC/k9qaBExtz9u8vYV6 wa+8bP4AAAAAAAA= --------------ms030001000802070007020408--
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