{"id":32,"date":"2010-11-06T10:47:11","date_gmt":"2010-11-06T10:47:11","guid":{"rendered":"http:\/\/lisas.de\/~alex\/?p=149"},"modified":"2026-03-30T22:41:23","modified_gmt":"2026-03-30T20:41:23","slug":"raid-away","status":"publish","type":"post","link":"https:\/\/lisas.de\/luges\/index.php\/2010\/11\/06\/raid-away\/","title":{"rendered":"RAID away"},"content":{"rendered":"<p>During the last week I&#8217;ve replaced the disks of my software RAID with larger ones as the capacity was exceeded. While this is theoretically an easy task, I had to learn a few things along the way:<\/p>\n<ul>\n<li>Trying to perform such an upgrade on a headless system without console will fail.<\/li>\n<li><code>fdisk<\/code> silently fails to parse integer values larger than 2147483647.<\/li>\n<li>The <code>md<\/code> superblock is located at the end of the partition\/disk that you add to the RAID.<\/li>\n<li>If the kernel associates the complete drive to a specific <code>md<\/code> device instead of the last partition, blocking the use of other partitions for other <code>md<\/code> devices, resize the last partition to leave some (wasted) space at the end to ensure that the end of the last RAID partition differs from the end of the drive.<\/li>\n<li>Some manufactures build &#8216;green&#8217; disks that constantly unload\/load their heads, causing the drive to run out of spec in a very short time. If the manufacturer provides a DOS tool to correct that behavior, a pretty easy solution is to <a title=\"Motherboard Flash Boot CD from Linux Mini HOWTO\" href=\"http:\/\/www.nenie.org\/misc\/flashbootcd.html\">put it onto a bootable CD<\/a>.<\/li>\n<li>This <a title=\"RAID stride calculation\" href=\"http:\/\/busybox.net\/~aldot\/mkfs_stride.html\">stride calculation script<\/a> helps to optimize the performance of the\u00a0filesystem\u00a0running on a RAID5.<\/li>\n<li><a title=\"Re: Use of WD20EARS with MDADM\" href=\"http:\/\/marc.info\/?l=linux-raid&amp;m=126979373211736\">Cheap desktop drives might be a bad choice for a RAID<\/a>, if they break during the first re-sync of the RAID you can try to recover your data by <a title=\"RAID 1 Shrinking\" href=\"http:\/\/lisas.de\/~adrian\/?p=689\">re-creating the RAID<\/a> &#8211; Thanks, Adrian!<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>During the last week I&#8217;ve replaced the disks of my software RAID with larger ones as the capacity was exceeded. While this is theoretically an easy task, I had to learn a few things along the way: Trying to perform such an upgrade on a headless system without console will fail. fdisk silently fails to [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-32","post","type-post","status-publish","format-standard","hentry","category-luges"],"_links":{"self":[{"href":"https:\/\/lisas.de\/luges\/index.php\/wp-json\/wp\/v2\/posts\/32","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lisas.de\/luges\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lisas.de\/luges\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lisas.de\/luges\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lisas.de\/luges\/index.php\/wp-json\/wp\/v2\/comments?post=32"}],"version-history":[{"count":2,"href":"https:\/\/lisas.de\/luges\/index.php\/wp-json\/wp\/v2\/posts\/32\/revisions"}],"predecessor-version":[{"id":1355,"href":"https:\/\/lisas.de\/luges\/index.php\/wp-json\/wp\/v2\/posts\/32\/revisions\/1355"}],"wp:attachment":[{"href":"https:\/\/lisas.de\/luges\/index.php\/wp-json\/wp\/v2\/media?parent=32"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lisas.de\/luges\/index.php\/wp-json\/wp\/v2\/categories?post=32"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lisas.de\/luges\/index.php\/wp-json\/wp\/v2\/tags?post=32"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}