Date: Sun, 23 Mar 2014 13:45:37 -0500 From: Karl Denninger <karl@denninger.net> To: freebsd-stable@freebsd.org Subject: Re: ZFS cautions (pool flag additions committed) Message-ID: <532F2BD1.4080606@denninger.net> In-Reply-To: <532F2B1B.5090702@egr.msu.edu> References: <532F1ED8.8010004@denninger.net> <532F2B1B.5090702@egr.msu.edu>
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This is a cryptographically signed message in MIME format. --------------ms060503020806060005010306 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable On 3/23/2014 1:42 PM, Adam McDougall wrote: > On 03/23/2014 13:50, Karl Denninger wrote: >> When ZFS code imports are brought forward that add feature flags there= >> is a potential time bomb for existing users in that creation of a new >> pool becomes non-revertible (except read-only!) with regard to mountin= g >> on older revisions of the code. >> >> The same thing happens if you do a "zpool upgrade" of course, but at >> least that's an explicit act. You might not realize that you're at ri= sk >> on a pool create, however, unless you **carefully** scrutinize the fla= gs >> that were on the last version compared against the current one. >> >> The primary "gotcha" here occurs if you don't upgrade your emergency >> boot media and for some reason you need to boot from a CD or USB key -= - >> you can be left SEVERELY screwed, and since -RELEASE is typically not >> rebuilt when this happens if you don't have a second machine laying >> around on which you can build a RELEASE image.... >> >> I've caught this twice now since 10.0-RELEASE shipped and, while I >> haven't been bit by it, it serves as a caution because eventually >> someone tracking -STABLE is going to get badly hurt and be left with a= n >> unrepairable system. IMHO there should be some sort of notice on the >> list when new zpool feature flags show up so you're fairly warned that= >> building a new emergency boot media copy is required if you intend to >> track -STABLE on a continuing basis. >> > I understand your point, but you can also get snapshot isos built prett= y > regulary, so there should be no need to build your own in an emergency:= > > ftp://ftp.freebsd.org/pub/FreeBSD/snapshots/ISO-IMAGES/ > > If weekly is not good enough, you can get daily: > > https://pub.allbsd.org/FreeBSD-snapshots/ It just seems to have become a more-frequent thing of late and I thought = people ought to pay attention to it. You're definitely going to be unhappy if you wind up with recovery media = that won't mount your disks! --=20 -- Karl karl@denninger.net --------------ms060503020806060005010306 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 KoZIhvcNAQcBMBwGCSqGSIb3DQEJBTEPFw0xNDAzMjMxODQ1MzdaMCMGCSqGSIb3DQEJBDEW BBS387Itq0r9hgnyGFLpRuSsmrt8gzBsBgkqhkiG9w0BCQ8xXzBdMAsGCWCGSAFlAwQBKjAL BglghkgBZQMEAQIwCgYIKoZIhvcNAwcwDgYIKoZIhvcNAwICAgCAMA0GCCqGSIb3DQMCAgFA MAcGBSsOAwIHMA0GCCqGSIb3DQMCAgEoMIG0BgkrBgEEAYI3EAQxgaYwgaMwgZ0xCzAJBgNV BAYTAlVTMRAwDgYDVQQIEwdGbG9yaWRhMRIwEAYDVQQHEwlOaWNldmlsbGUxGTAXBgNVBAoT EEN1ZGEgU3lzdGVtcyBMTEMxHDAaBgNVBAMTE0N1ZGEgU3lzdGVtcyBMTEMgQ0ExLzAtBgkq hkiG9w0BCQEWIGN1c3RvbWVyLXNlcnZpY2VAY3VkYXN5c3RlbXMubmV0AgEIMIG2BgsqhkiG 9w0BCRACCzGBpqCBozCBnTELMAkGA1UEBhMCVVMxEDAOBgNVBAgTB0Zsb3JpZGExEjAQBgNV BAcTCU5pY2V2aWxsZTEZMBcGA1UEChMQQ3VkYSBTeXN0ZW1zIExMQzEcMBoGA1UEAxMTQ3Vk YSBTeXN0ZW1zIExMQyBDQTEvMC0GCSqGSIb3DQEJARYgY3VzdG9tZXItc2VydmljZUBjdWRh c3lzdGVtcy5uZXQCAQgwDQYJKoZIhvcNAQEBBQAEggIAHX2CPesWOWU8hMPSYQOV34EKYb6w BUJQDjf2NX3k5mwYC+IBubjhpuikSbiE8Uexk1uBd4fu3fOHOkMQvMGKEcKuOpIo0fmxUiqh GGI/UeusHSU55PvKG4G7Zw1jmzl6gVzCBqVsqW3OoCXfFqeqpBTx+bU9t0Q0opPmr3F5WVCz aqjxIeXLalv3y5jF7ufnTCCxpcLZQgwkUn02YfLzmxxxNuSX6FbRu8synY0f862x8agBMoS6 FLe+aHeFvsryiBnosusGm1DHqbPLruqjoTfMZ1slK0AdpyyATdERpHXzfq9u6UAqmzM3zbgI 3Gzku4EJoPH/M6GHqtgLhDd7fg30EYiNfiuS+SclVu+Qi+pWoea9InumozgtLfV0vYJ02UR/ lkKGfYxHewxSIKUmhIh2jcg2t8y4fCDyVC7CUmnM9t+0MVLPpu1w5/6f5kd6Wq17THlt0LhM xrOGW1M94fuanAkG2BIU1sAjBK6eqh9//GEny2GwAkgMb/npICtfqgtPY7GPPufr6j/P+OlD qSL63IHvQdbWNHv141dQY3QMGhwv0iQsOhhgar3fhw5ujNzUJFr4CXBVFE8ZQ1oHHMdHT3ME 6bdjtYP5WkEiHgOcCUdm0575zWGnGpmOC+VTPZX1EyKziog0hkSly9f5BcaqP9QIC1Paupo4 ZIy6qbQAAAAAAAA= --------------ms060503020806060005010306--
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