There was recently a discussion on the NetWorker mailing list that was sparked by someone asking what sort of LTO-4 library would be recommended by the community.<\/p>\n
This led to some very interesting and useful feedback to the person posing the question. A lot of people had feedback about different libraries they’d used \u2013 both good and bad \u2013 and questions to ask, such as slot count and CAP\/Mail slot size. I felt it was also important to weigh in on media movement speed, as I think this is often something which is disregarded when evaluating libraries \u2013 even though it often can play a factor in backup throughput, usability and perceived performance.<\/p>\n
Rather than summarise myself, here’s what I had to say on the topic then:<\/p>\n
Too often people worry about the speed and capacity of the media, and forget about the incidental factors, such as robotic movement times and even load\/seek time on the media. These can play an important factor in backup and – more importantly, really – recovery schedules. When it comes to measuring backup performance, the sequence of “returning to slot, picking next tape, placing in drive” can actually start to make a significant impact on what I refer to as your overnight “backup bandwidth”. If it takes say, 70 seconds for one library to do it and your drives write at 160MB\/s, then that’s a 10GB interruption to your backups. If another library can do the same thing in 30 seconds, that’s just a 4.7GB interruption to your backups. (I’m deliberately excluding load\/unload times of the media, because in a realistic comparison it would be the same drives in both libraries…) Repeat that say, 30 times a night, and suddenly you’re deciding whether you can afford to lose 300GB in backup time a night or 141GB in backup time a night. For bigger sites, these numbers can actually become very important.<\/em><\/p>\n If you are considering a new tape library, be sure to ask about not only the “easy” numbers, such as how much it costs, how much maintenance costs, and how fast the drives read\/write, but also the more challenging numbers \u2013 how much time it takes to move media around.<\/p>\n","protected":false},"excerpt":{"rendered":" There was recently a discussion on the NetWorker mailing list that was sparked by someone asking what sort of LTO-4…<\/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":[13,16,17],"tags":[981],"class_list":["post-178","post","type-post","status-publish","format-standard","hentry","category-general-thoughts","category-networker","category-policies","tag-tape-library"],"aioseo_notices":[],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pKpIN-2S","jetpack_sharing_enabled":true,"jetpack_likes_enabled":true,"_links":{"self":[{"href":"https:\/\/nsrd.info\/blog\/wp-json\/wp\/v2\/posts\/178","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=178"}],"version-history":[{"count":1,"href":"https:\/\/nsrd.info\/blog\/wp-json\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":7685,"href":"https:\/\/nsrd.info\/blog\/wp-json\/wp\/v2\/posts\/178\/revisions\/7685"}],"wp:attachment":[{"href":"https:\/\/nsrd.info\/blog\/wp-json\/wp\/v2\/media?parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nsrd.info\/blog\/wp-json\/wp\/v2\/categories?post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nsrd.info\/blog\/wp-json\/wp\/v2\/tags?post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}