{"id":2982,"date":"2021-12-01T14:05:57","date_gmt":"2021-12-01T22:05:57","guid":{"rendered":"https:\/\/rglinuxtech.com\/?p=2982"},"modified":"2021-12-01T14:05:57","modified_gmt":"2021-12-01T22:05:57","slug":"disks-not-so-s-m-a-r-t-after-all","status":"publish","type":"post","link":"https:\/\/rglinuxtech.com\/?p=2982","title":{"rendered":"Disks &#8211; Not so S.M.A.R.T. After All?"},"content":{"rendered":"<p>More problems with severe disk performance degradation, but SMART still shows the disc as &#8216;OK&#8217;..<\/p>\n<p>This has now occurred three times over the last 2 years or so, with 1TB and 2TB disks that were around 4+ years old (in continuous use..)..<\/p>\n<p>The contents were still accessible, but data transfer was <span style=\"text-decoration: underline;\">extremely<\/span> slow &#8211; around 250KiB\/s to 1MiB\/s.. (and start\/stop..)<\/p>\n<div id=\"attachment_2983\" style=\"width: 968px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/rglinuxtech.com\/wp_rglinuxtech\/wp-content\/uploads\/2021\/12\/data01-bad_disk-smart-data.png\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-2983\" class=\"wp-image-2983 size-full\" src=\"https:\/\/rglinuxtech.com\/wp_rglinuxtech\/wp-content\/uploads\/2021\/12\/data01-bad_disk-smart-data.png\" alt=\"smart_bad_disk\" width=\"958\" height=\"772\" srcset=\"https:\/\/rglinuxtech.com\/wp_rglinuxtech\/wp-content\/uploads\/2021\/12\/data01-bad_disk-smart-data.png 958w, https:\/\/rglinuxtech.com\/wp_rglinuxtech\/wp-content\/uploads\/2021\/12\/data01-bad_disk-smart-data-300x242.png 300w, https:\/\/rglinuxtech.com\/wp_rglinuxtech\/wp-content\/uploads\/2021\/12\/data01-bad_disk-smart-data-768x619.png 768w\" sizes=\"auto, (max-width: 958px) 100vw, 958px\" \/><\/a><p id=\"caption-attachment-2983\" class=\"wp-caption-text\">Bad Disk &#8211; SMART Data<\/p><\/div>\n<p>I was &#8211; eventually &#8211; able to recover the contents, but the whole process took many days.\u00a0\u00a0\u00a0\u00a0 I tried <strong>dd<\/strong>&#8216;ing the disk, but this seemed to go on for ever, so I reverted to copying small batches of files, and checking the destination contents as I went.\u00a0\u00a0\u00a0\u00a0\u00a0 It would appear that the things to watch out for are &#8216;Write Error Rate&#8217; and &#8216;Read Error Rate&#8217;, although SMART does not show these as too high?\u00a0\u00a0\u00a0\u00a0\u00a0 The Threshold for &#8216;Write Error Rate&#8217; is <strong>zero<\/strong>, so I would have thought that a value of <strong>8<\/strong> would be flagged?<\/p>\n<p>Obviously this is not very scientific, there is no &#8216;before\/after&#8217; and the scenario is very much &#8216;after the event&#8217;..\u00a0\u00a0\u00a0\u00a0 Eventually I started to see i\/o errors, so the snails-pace data recovery was just in time..\u00a0\u00a0\u00a0\u00a0 Other disks (2TB) of the same brand and vintage are still OK, but these are being swapped out &#8211; just in case..<\/p>\n<p><em>Robert Gadsdon.\u00a0\u00a0 November 30, 2021.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>More problems with severe disk performance degradation, but SMART still shows the disc as &#8216;OK&#8217;.. This has now occurred three times over the last 2 years or so, with 1TB and 2TB disks that were around 4+ years old (in continuous use..).. The contents were still accessible, but data transfer was extremely slow &#8211; around 250KiB\/s to <span class=\"excerpt-dots\">&hellip;<\/span> <a class=\"more-link\" href=\"https:\/\/rglinuxtech.com\/?p=2982\"><span class=\"more-msg\">Continue reading &rarr;<\/span><\/a><\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[6,1298,15],"tags":[2445,2443,2447,2444,2446],"class_list":["post-2982","post","type-post","status-publish","format-standard","hentry","category-crash-and-burn","category-hardware","category-linux-2","tag-data-xfer-very-slow","tag-disk-fail","tag-read-error","tag-smart-shows-ok","tag-write-error"],"_links":{"self":[{"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/posts\/2982","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2982"}],"version-history":[{"count":3,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/posts\/2982\/revisions"}],"predecessor-version":[{"id":2986,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/posts\/2982\/revisions\/2986"}],"wp:attachment":[{"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2982"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2982"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2982"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}