Date: Sat, 21 Jan 2017 12:12:17 -0600 From: Karl Denninger <karl@denninger.net> To: freebsd-arm@freebsd.org Subject: Re: how to measure microsd wear Message-ID: <1d757b3b-67d2-b29b-ba01-89b462b0019f@denninger.net> In-Reply-To: <1485021485.34897.185.camel@freebsd.org> References: <16821b7c-e300-97fc-36e5-a508b22c21b8@zyxst.net> <1485021485.34897.185.camel@freebsd.org>
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This is a cryptographically signed message in MIME format. --------------ms060108050507040608090809 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable On 1/21/2017 11:58, Ian Lepore wrote: > On Sat, 2017-01-21 at 15:46 +0000, tech-lists wrote: >> Hello list, >> >> How would one measure microsd wear? Is there a utility like >> smartmontools (I think this only works for regular hard drives) but >> for >> microsd? >> >> many thanks, > There is basically no way to see what's going on in the flash array of > an sdcard. The microcontrollers in modern sd cards have complex wear- > leveling algorithms which are completely transparent to the outside > world. This is true. > On the plus side, most of what you see in the way of warnings and scare= > stories about wearing out sd cards is pure BS. I've got systems here > that have been running for literally years on the same sdcard, and that= > card is being used for swap, and routine data storage like syslog (on > an embedded system that logs status and progress pretty much > continuously 24x7 for years). I've seen a few sd cards die over the > years, but I've never been able to say it was because of how much was > written to them (indeed, the dead ones I've got weren't in service long= > before they died). > This, however, is total nonsense. I've had multiple SD card failures in build/test/high-volume write environments on the PI2 series over the last year and change. There are two general ways in which you will see failures: 1. The card write-locks itself. This is a defensive move by the controller when it determines that it cannot reallocate a failed block during a write (e.g. it's out of spares) OR it takes an unrecoverable read error. 2. The card loses its allocation map (in which case you're completely screwed; it will show up as zero size if you manage to get it mounted somewhere.) If you get a type 1 failure you can copy everything on the card off; provided you do not attempt to write it, you will not get errors. Prior to a fairly recent MFC if you had soft-updates on and took a Type 1 failure you'd get an instant panic; this has been (I believe entirely) fixed. In the event you get a Type 2 failure there's nothing you can do. In both cases the card is junk if it happens. --=20 Karl Denninger karl@denninger.net <mailto:karl@denninger.net> /The Market Ticker/ /[S/MIME encrypted email preferred]/ --------------ms060108050507040608090809 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 BlwwggZYMIIEQKADAgECAgE9MA0GCSqGSIb3DQEBCwUAMIGQMQswCQYDVQQGEwJVUzEQMA4G A1UECBMHRmxvcmlkYTESMBAGA1UEBxMJTmljZXZpbGxlMRkwFwYDVQQKExBDdWRhIFN5c3Rl bXMgTExDMRwwGgYDVQQDExNDdWRhIFN5c3RlbXMgTExDIENBMSIwIAYJKoZIhvcNAQkBFhND dWRhIFN5c3RlbXMgTExDIENBMB4XDTE2MTIxODE5NDUzNVoXDTIxMTIxNzE5NDUzNVowVzEL MAkGA1UEBhMCVVMxEDAOBgNVBAgTB0Zsb3JpZGExGTAXBgNVBAoTEEN1ZGEgU3lzdGVtcyBM TEMxGzAZBgNVBAMUEmthcmxAZGVubmluZ2VyLm5ldDCCAiIwDQYJKoZIhvcNAQEBBQADggIP ADCCAgoCggIBAM2N5maxs7NkoY9g5NMxFWll0TYiO7gXrGZTo3q25ZJgNdPMwrntLz/5ewE9 07TEbwJ3ah/Ep9BfZm7JF9vTtE1HkgKtXNKi0pawNGm1Yn26Dz5AbUr1byby6dFtDJr14E07 trzDCtRRvTkOVSBj6PQPal0fAnDtkIYQBVcuMkXkuMCtyfE95pjm8g4K9l7lAcKii3T1/3rE hCc1o2nBnb7EN1/XwBeCDGB+I2SN/ftZDbKQqGAF5q9dUn+iXU7Z/CVSfUWmhVh6cVZA4Ftv TglUqj410OuPx+cUQch3h1kFgsuhQR63HiJc3HbRJllHsV0rihvL1CjeARQkhnA6uY9NLFST p5I/PfzBzW2MSmtN/tGZvmfKKnmtbfUNgkzbIR1K3lsum+yEL71kB93Xtz/4f1demEx5c8TJ RBIniDHjDeLGK1aoBu8nfnvXAvgthFNTWBOEoR49AHEPjC3kZj0l8JQml1Y8bTQD5gtC5txl klO60WV0EufU7Hy9CmynMuFtjiA2v71pm097rXeCdrAKgisdYeEESB+SFrlY65rLiLv4n8o1 PX7DqRfqKkOYIakZ0ug/yHVKcq2EM3RiJxwzls5gT70CoOBlKbrC98O8TA6teON0Jq30M06t NTI2HhvNbJDLbBH+Awf4h1UKB+0ufENwjVvF5Jfz8Ww/FaSDAgMBAAGjgfQwgfEwNwYIKwYB BQUHAQEEKzApMCcGCCsGAQUFBzABhhtodHRwOi8vY3VkYXN5c3RlbXMubmV0Ojg4ODgwCQYD VR0TBAIwADARBglghkgBhvhCAQEEBAMCBaAwCwYDVR0PBAQDAgXgMCwGCWCGSAGG+EIBDQQf Fh1PcGVuU1NMIEdlbmVyYXRlZCBDZXJ0aWZpY2F0ZTAdBgNVHQ4EFgQUpfAI3y+751pp9A0w 6vJHx8RoR/MwHwYDVR0jBBgwFoAUJHGbnYV9/N3dvbDKkpQDofrTbTUwHQYDVR0RBBYwFIES a2FybEBkZW5uaW5nZXIubmV0MA0GCSqGSIb3DQEBCwUAA4ICAQBiB6MlugxYJdccD8boZ/u8 d8VxmLkJCtbfyYHRjYdyoABLW5hE3k3xSpYCM9L7vzWyV/UWwDYKi4ZzxHo4g+jG/GQZfKhx v38BQjL2G9xD0Hn2d+cygOq3UPjVYlbbfQoew6JbyCFXrrZ7/0jvRMLAN2+bRC7ynaFUixPH Whnj9JSH7ieYdzak8KN+G2coIC2t2iyfXVKehzi5gdNQ0vJ7+ypbGsRm4gE8Mdo9N/WgFPvZ HPFqR9Dwas7Z+aHwOabpk5r/336SyjOaZsn3MqKJQZL6GqDKusVOCWt+9uFAD8kadg7FetZe atIoD9I+zbp59oVoMnkMDMx7Hi85faU03csusqMGsjSsAzWSI1N8PJytZlchLiykokLKc3OL G87QKlErotlou7cfPX2BbEAH5wmkj9oiqZhxIL/wwAUA+PkiTbEmksKBNompSjUq/6UsR8EA s74gnu17lmijv8mrg2qMlwRirE7qG8pnE8egLtCDxcjd0Of9WMi2NJskn0/ovC7P+J60Napl m3ZIgPJst1piYSE0Zc1FIat4fFphMfK5v4iLblo1tFSlkdx1UNDGdg/U+LaXkNVXlMp8fyPm R80V6cIrCAlEWnBJNxG1UyfbbsvNMCCZBM4faGGsR/hhQOiydlruxhjL6P8J2WV8p11DdeGx KymWoil2s1J5WTGCBRMwggUPAgEBMIGWMIGQMQswCQYDVQQGEwJVUzEQMA4GA1UECBMHRmxv cmlkYTESMBAGA1UEBxMJTmljZXZpbGxlMRkwFwYDVQQKExBDdWRhIFN5c3RlbXMgTExDMRww GgYDVQQDExNDdWRhIFN5c3RlbXMgTExDIENBMSIwIAYJKoZIhvcNAQkBFhNDdWRhIFN5c3Rl bXMgTExDIENBAgE9MA0GCWCGSAFlAwQCAwUAoIICTTAYBgkqhkiG9w0BCQMxCwYJKoZIhvcN AQcBMBwGCSqGSIb3DQEJBTEPFw0xNzAxMjExODEyMTdaME8GCSqGSIb3DQEJBDFCBEDEnJg6 qMo9Djs6EXgBN3nbnzeGakoN7fCmSGjbd+8enQqIlnRLQL8vPxhJDInOs0RE1+FU8iKLksmG 9JRBIjL7MGwGCSqGSIb3DQEJDzFfMF0wCwYJYIZIAWUDBAEqMAsGCWCGSAFlAwQBAjAKBggq hkiG9w0DBzAOBggqhkiG9w0DAgICAIAwDQYIKoZIhvcNAwICAUAwBwYFKw4DAgcwDQYIKoZI hvcNAwICASgwgacGCSsGAQQBgjcQBDGBmTCBljCBkDELMAkGA1UEBhMCVVMxEDAOBgNVBAgT B0Zsb3JpZGExEjAQBgNVBAcTCU5pY2V2aWxsZTEZMBcGA1UEChMQQ3VkYSBTeXN0ZW1zIExM QzEcMBoGA1UEAxMTQ3VkYSBTeXN0ZW1zIExMQyBDQTEiMCAGCSqGSIb3DQEJARYTQ3VkYSBT eXN0ZW1zIExMQyBDQQIBPTCBqQYLKoZIhvcNAQkQAgsxgZmggZYwgZAxCzAJBgNVBAYTAlVT MRAwDgYDVQQIEwdGbG9yaWRhMRIwEAYDVQQHEwlOaWNldmlsbGUxGTAXBgNVBAoTEEN1ZGEg U3lzdGVtcyBMTEMxHDAaBgNVBAMTE0N1ZGEgU3lzdGVtcyBMTEMgQ0ExIjAgBgkqhkiG9w0B CQEWE0N1ZGEgU3lzdGVtcyBMTEMgQ0ECAT0wDQYJKoZIhvcNAQEBBQAEggIAbfzJyLvA2uDx zJOOmAv8mDca+ZoYHqpbp+T38jKNw4bb1rGsbCrX9WOVYnRrPC9RNrX/xBsSwTrcmrAeBwjn pCln5xcd6dAwgkfZ3AjDaUi2EOQTsHcKZdApqyYb6qUj5/sCO8qNw4917KWr1rKFg71dgshK NmDMWy4XG86Q1EtwmQjg7na9xBp2fhkvTaa2i0wsDJmTeuz+QRLA1c/Kt1kpm5I5wL6E/jFg jQ3k2up2vu/laa80YVoDL5mrGLBL+tHz69Ry5yeTq0LjUv/nbbb07vuJ/FLoXtLBAA9FORKo 5D49bN3RWhJ3Gj+GRD69rh0Y/wKFvORB6BPUvV28cTz22asMUo0+bndhCTfaqF2i8PziARec z5jkE5Gc4cIFU/Kf7keWMiyXvTHATP3FKSzLu06MS+Qf8ZbLC6vhkJV24+rlPEhMCFfEFrmm 8G01koSOJCcYMfEAxBe7/2DZy1BXn6zM5zLs+AgxZJTbcpmGHbsxq0afvNr5jzJvMzuQzGK+ QUrVirY4XI5hoJ+aSy8gV7qw3m6CL3f/U3qIPLOhxqkmRNWvCt7XZ/ESz6akiZ4QvC7b+YRW 7lpSc/Sg0miic5MRM4W3rgBCvcXyJmP1vIbgers5jwTprystrKrRAiotvUP1uuthrs4rtNJA 3R9ee4hsbYGAgyB13JZeR+sAAAAAAAA= --------------ms060108050507040608090809--
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