{"id":446,"date":"2009-07-13T06:32:38","date_gmt":"2009-07-12T20:32:38","guid":{"rendered":"http:\/\/nsrd.wordpress.com\/?p=446"},"modified":"2009-07-13T06:32:38","modified_gmt":"2009-07-12T20:32:38","slug":"basics-networker-differential-levels","status":"publish","type":"post","link":"https:\/\/nsrd.info\/blog\/2009\/07\/13\/basics-networker-differential-levels\/","title":{"rendered":"Basics &#8211; NetWorker differential levels"},"content":{"rendered":"<p>One question I&#8217;m often asked by people who haven&#8217;t used differential levels within NetWorker is <em>what is the purpose of the different levels<\/em><em>? <\/em>In particular, this tends to lead to <em>if I&#8217;m going to implement a differential backup, what level should I choose?<\/em><\/p>\n<p>While multiple differential levels grants considerable extra flexibility to NetWorker backups schedules, it can be confusing to the uninitiated. After all, if you&#8217;re currently only using fulls and incrementals, but want to insert a differential level, should you choose a level 1, level 2, level 3, etc.?<\/p>\n<p>If you&#8217;re only using <em>one<\/em> differential level, it really doesn&#8217;t matter which level you use (though I have a suggestion); that is, all 9 differential levels interact with fulls and incrementals in exactly the same way when they are the <em>only<\/em> differential level used.<\/p>\n<p>For this reason, if I&#8217;m only using one differential level in a schedule, I tend to use level 5. There&#8217;s a very simple reason for this \u2013 if at a later point I need to insert additional differential levels, then I can insert either lower or higher number levels around the 5 without having to change the level I&#8217;ve already been using, and with maximum flexibility as to the number of differential levels I can insert.<\/p>\n<p>Now, how do they relate to one another?<\/p>\n<ul>\n<li>A differential level 1 will backup all changes since the last full.<\/li>\n<li>A differential level 2 will backup all the changes since the last full <em>or<\/em> the last differential level 1, whichever is most recent.<\/li>\n<li>A differential level 3 will backup all the changes since the last full <em>or<\/em> the last differential level 2, or the last differential level 1, whichever is most recent.<\/li>\n<li>etc.<\/li>\n<\/ul>\n<p>I.e., any differential level <em>X<\/em> will backup all files that have changed since <em>either<\/em> the last full <em>or<\/em> the last <em>X-n<\/em> level backup, whichever is more recent.<\/p>\n<p>Now, in weekly schedules, there&#8217;s usually little point in using multiple differential levels. Where they come into play more usefully is in monthly or even more lengthy schedules such as quarterly backups. I&#8217;ve previously discussed using differential levels in <a title=\"Monthly schedules\" href=\"https:\/\/nsrd.info\/blog\/2009\/02\/05\/monthly-rather-than-weekly-fulls-using-backup-to-disk\/\" target=\"_blank\">monthly schedules here<\/a>, and <a title=\"Enterprise Systems Backup and Recovery: A corporate insurance policy\" href=\"http:\/\/www.amazon.com\/gp\/redirect.html?ie=UTF8&amp;location=http%3A%2F%2Fwww.amazon.com%2FEnterprise-Systems-Backup-Recovery-Corporate%2Fdp%2F1420076396%3Fie%3DUTF8%26s%3Dbooks%26qid%3D1221104920%26sr%3D8-1&amp;tag=entesystbacka-20&amp;linkCode=ur2&amp;camp=1789&amp;creative=9325\" target=\"_blank\">in my book<\/a> I give a reasonably complete example of quarterly full backup schedules for small-change low-access servers.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>One question I&#8217;m often asked by people who haven&#8217;t used differential levels within NetWorker is what is the purpose of&hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[6,16],"tags":[42,43,51,55,56,58,59,86,87,319,532],"class_list":["post-446","post","type-post","status-publish","format-standard","hentry","category-basics","category-networker","tag-42","tag-43","tag-51","tag-55","tag-56","tag-58","tag-59","tag-86","tag-87","tag-differential","tag-level"],"aioseo_notices":[],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pKpIN-7c","jetpack_sharing_enabled":true,"jetpack_likes_enabled":true,"_links":{"self":[{"href":"https:\/\/nsrd.info\/blog\/wp-json\/wp\/v2\/posts\/446","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nsrd.info\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nsrd.info\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nsrd.info\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/nsrd.info\/blog\/wp-json\/wp\/v2\/comments?post=446"}],"version-history":[{"count":0,"href":"https:\/\/nsrd.info\/blog\/wp-json\/wp\/v2\/posts\/446\/revisions"}],"wp:attachment":[{"href":"https:\/\/nsrd.info\/blog\/wp-json\/wp\/v2\/media?parent=446"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nsrd.info\/blog\/wp-json\/wp\/v2\/categories?post=446"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nsrd.info\/blog\/wp-json\/wp\/v2\/tags?post=446"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}