{"id":9129,"date":"2008-07-17T10:24:00","date_gmt":"1999-11-29T20:00:00","guid":{"rendered":"https:\/\/aidanfinn.com\/?p=9129"},"modified":"2008-07-17T10:24:00","modified_gmt":"1999-11-29T20:00:00","slug":"hyper-v-controllers-ide-or-scsi","status":"publish","type":"post","link":"https:\/\/aidanfinn.com\/?p=9129","title":{"rendered":"Hyper-V Controllers: IDE or SCSI?"},"content":{"rendered":"<p>There&#8217;s been plenty of blog posts out there saying that there is no support for SCSI in Hyper-V.\u00a0 That&#8217;s not true.\u00a0 What is true is this.\u00a0 You can use SCSI controllers for disks but not for your boot disk.\u00a0 Your boot disk must be on an IDE controller.<\/p>\n<p>When using emulated storage controllers, i.e. no integration components then IDE is slower than SCSI.\u00a0 However, there is no discernable difference between SCSI and IDE when using sythentic drivers, i.e. integration components or VM additions.<\/p>\n<p><strong><u>Setting Up VM&#8217;s<\/u><\/strong><\/p>\n<p>How do you set up your VM&#8217;s?\u00a0 You have no choice about your boot disk.\u00a0 You must use a disk connected to the IDE controller.\u00a0 You can&#8217;t move that to the SCSI controller because you cannot boot from a Hyper-V SCSI controller.\u00a0 Lightweight VM&#8217;s can probably put everything on one virtual disk and run on the IDE controller.<\/p>\n<p>However, best practice is to separate your data\/workload from your operating system.\u00a0 Consider a virtual application server where the operating system is on C: and the workload is on D:.\u00a0 C: will be a virtual disk on the IDE controller.\u00a0 D: should be a virtual disk on a SCSI controller if you don&#8217;t have integration components.\u00a0 This makes the most of the underlying Hyper-V architecture and optimises CPU utilisation on the host server.\u00a0 However, if you have integration components then it makes no difference whether you use SCSI or IDE for the workload disk.<\/p>\n<p>What really makes a difference is the underlying physical storage and the types of VHD that you use.\u00a0 Passthrough disks are physical speed.\u00a0 Fixed Sized VHD currently get to within 6% of the speed of the underlying physical LUN, assuming you have 1 VHD per LUN.\u00a0 Dynamic and Differencing VHD&#8217;s have great impacts on performance.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>There&#8217;s been plenty of blog posts out there saying that there is no support for SCSI in Hyper-V.\u00a0 That&#8217;s not true.\u00a0 What is true is this.\u00a0 You can use SCSI controllers for disks but not for your boot disk.\u00a0 Your boot disk must be on an IDE controller. When using emulated storage controllers, i.e. no &hellip; <a href=\"https:\/\/aidanfinn.com\/?p=9129\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Hyper-V Controllers: IDE or SCSI?&#8221;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_uf_show_specific_survey":0,"_uf_disable_surveys":false,"footnotes":""},"categories":[20],"tags":[],"class_list":["post-9129","post","type-post","status-publish","format-standard","hentry","category-hyper-v"],"aioseo_notices":[],"jetpack_featured_media_url":"","amp_enabled":true,"_links":{"self":[{"href":"https:\/\/aidanfinn.com\/index.php?rest_route=\/wp\/v2\/posts\/9129","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/aidanfinn.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/aidanfinn.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/aidanfinn.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/aidanfinn.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=9129"}],"version-history":[{"count":0,"href":"https:\/\/aidanfinn.com\/index.php?rest_route=\/wp\/v2\/posts\/9129\/revisions"}],"wp:attachment":[{"href":"https:\/\/aidanfinn.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=9129"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/aidanfinn.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=9129"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/aidanfinn.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=9129"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}