{"id":11419,"date":"2011-07-28T17:51:00","date_gmt":"2011-07-28T17:51:00","guid":{"rendered":"https:\/\/aidanfinn.com\/?p=11419"},"modified":"2011-07-28T17:51:00","modified_gmt":"2011-07-28T17:51:00","slug":"hyper-v-replica-dr-strategy-musings-vs-what-we-can-do-now","status":"publish","type":"post","link":"https:\/\/aidanfinn.com\/?p=11419","title":{"rendered":"Hyper-V Replica DR Strategy Musings VS What We Can Do Now"},"content":{"rendered":"<p>See my more recent <a href=\"https:\/\/aidanfinn.com\/?p=12147\" target=\"_blank\">post <\/a>which talks in great detail about how Hyper-V Replica works and how to use it.<\/p>\n<p>At WPC11, Microsoft introduced (at a very high level) a new feature of Windows 8 (2012?) Server called <a href=\"https:\/\/aidanfinn.com\/?p=11334\" target=\"_blank\">Hyper-V Replica<\/a>.\u00a0 This came up in conversation in meetings yesterday and I immediately thought that customers in the SMB space, and even those in the corporate branch\/regional office would want to jump all over this \u2013 and need the <a href=\"https:\/\/aidanfinn.com\/?p=11406\" target=\"_blank\">upgrade rights<\/a>.<\/p>\n<p>Let\u2019s look at the DR options that you can use right now.<\/p>\n<p><strong><span style=\"text-decoration: underline;\">Backup Replication<\/span><\/strong><\/p>\n<p>One of the cheapest around and great for the SMB is replication by System Center Data Protection Manager 2010.\u00a0 With this solution you are leveraging the disk-disk functionality of your backup solution.\u00a0 The primary site DPM server backs up your virtual machines.\u00a0 The DR site DPM server replicates the backed up data and it\u2019s metadata to the DR site.\u00a0 During the invocation of the DR plan, virtual machines can be restored to an alternative (and completely different) Hyper-V host or cluster.<\/p>\n<p><a href=\"https:\/\/aidanfinn.com\/wp-content\/uploads\/2011\/07\/image13.png\"><img loading=\"lazy\" decoding=\"async\" style=\"background-image: none; padding-left: 0px; padding-right: 0px; display: block; float: none; margin-left: auto; margin-right: auto; padding-top: 0px; border: 0px;\" title=\"image\" src=\"https:\/\/aidanfinn.com\/wp-content\/uploads\/2011\/07\/image_thumb13.png\" border=\"0\" alt=\"image\" width=\"504\" height=\"175\" \/><\/a><\/p>\n<p>Using DPM is cost effective, and thanks to throttling, is light on the bandwidth and has none of the latency (distance) concerns of higher-end replication solutions.\u00a0 It is a bit more time consuming for the invocation.<\/p>\n<p>This is a nice economic way for an SMB or a branch\/regional office to do DR.\u00a0 It does require some work during invocation: that\u2019s the price you pay for a budget friendly solution that kills two marketing people with one stone \u2013 Hey; I like birds but I don\u2019t like marke \u2026Moving on \u2026<\/p>\n<p><strong><span style=\"text-decoration: underline;\">Third-Party Software Based Replication<\/span><\/strong><\/p>\n<p>The next solution up the ladder is a 3rd party software replication solution.\u00a0 At a high level there are two types:<\/p>\n<ul>\n<li>Host based solution: 1 host replicates to another host.\u00a0 These are often non-clustered hosts.\u00a0 This works out being quite expensive.<\/li>\n<li>Simulated cluster solution: This is where 1 host replicates to another.\u00a0 It can integrate with Windows Failover Clustering, or it may use it\u2019s own high availability solution.\u00a0 Again, this can be expensive, and solutions that feature their own high availability solution can possibly be flaky, maybe even being subject to split-brain active-active failures when the WAN link fails.<\/li>\n<li>Software based iSCSI storage: Some companies produce an iSCSI storage solution that you can install on a storage server.\u00a0 This gives you a budget SAN for clustering.\u00a0 Some of these solutions can include synchronous or asynchronous replication to a DR site.\u00a0 This can be much cheaper than a (hardware) SAN with the same features.\u00a0 Beware of using storage level backup with these \u2026 you need to know if VSS will create the volume snapshot within the volume that\u2019s being replicated.\u00a0 If it does, then you\u2019ll have your WAN link flooded with unnecessary snapshot replication to the DR site every time you run that backup job.<\/li>\n<\/ul>\n<p><a href=\"https:\/\/aidanfinn.com\/wp-content\/uploads\/2011\/07\/image14.png\"><img loading=\"lazy\" decoding=\"async\" style=\"background-image: none; padding-left: 0px; padding-right: 0px; display: block; float: none; margin-left: auto; margin-right: auto; padding-top: 0px; border: 0px;\" title=\"image\" src=\"https:\/\/aidanfinn.com\/wp-content\/uploads\/2011\/07\/image_thumb14.png\" border=\"0\" alt=\"image\" width=\"504\" height=\"135\" \/><\/a><\/p>\n<p>This solution gives you live replication from the production to the DR site.\u00a0 In theory, all you need to do to recover from a site failure is to power up the VMs in the DR site.\u00a0 Some solutions may do this automatically (beware of split brain active-active if the WAN link and heartbeat fails).\u00a0 You only need to touch backup during this invocation if the disaster introduced some corruption.<\/p>\n<p>Your WAN requirements can also be quite flexible with these solutions:<\/p>\n<ul>\n<li>Bandwidth: You will need at least 1 Gbps for Live Migration between sites.\u00a0 100 Mbps will suffice for Quick Migration (it still has a use!).\u00a0 Beyond that, you need enough bandwidth to handle data throughput for replication and that depends on change to your VMs\/replicated storage.\u00a0 Your backup logs may help with that analysis.<\/li>\n<li>Latency: Synchronous replication will require very low latency, e.g. &lt;2 MS.\u00a0 Check with the vendor.\u00a0 Asynchronous replication is much better at handling long distance and high latency connections.\u00a0 You may lose a few seconds of data during the disaster, but it\u2019ll cost you a lot less to maintain.<\/li>\n<\/ul>\n<p>I am not a fan of this type of solution.\u00a0 I\u2019ve been burned by this type of software with file\/SQL server replication in the past.\u00a0 I\u2019ve also seen it used with Hyper-V where compromises on backup had to be made.<\/p>\n<p><strong><span style=\"text-decoration: underline;\">SAN Replication<\/span><\/strong><\/p>\n<p>This is the most expensive solution, and is where the SAN does the replication at the physical storage layer.\u00a0 It is probably the simplest to invoke in an emergency, and depending on the solution, can allow you to create multi-site clusters, sometimes with CSVs that span the sites (and you need to plan very carefully if doing that).\u00a0 For this type of solutions you need:<\/p>\n<ul>\n<li>Quite an expensive SAN.\u00a0 That expense varies wildly.\u00a0 Some SANs include replication, and some really high end SANs require an additional replication license(s) to be purchased.<\/li>\n<li>Lots of high quality, and probably ultra low latency, WAN pipe.\u00a0 Synchronous replication will need a lot of bandwidth and very low latency connections.\u00a0 The benefit is (in theory) zero data loss during an invocation.\u00a0 When a write happens in site A on the SAN, then it happens in site B.\u00a0 Check with the manufacturer and\/or an <em>expert<\/em> in this technology (not honest Bob, the PC salesman, or even honest Janet, the person you buy your servers from).<\/li>\n<\/ul>\n<p><a href=\"https:\/\/aidanfinn.com\/wp-content\/uploads\/2011\/07\/image15.png\"><img loading=\"lazy\" decoding=\"async\" style=\"background-image: none; padding-left: 0px; padding-right: 0px; display: block; float: none; margin-left: auto; margin-right: auto; padding-top: 0px; border: 0px;\" title=\"image\" src=\"https:\/\/aidanfinn.com\/wp-content\/uploads\/2011\/07\/image_thumb15.png\" border=\"0\" alt=\"image\" width=\"504\" height=\"319\" \/><\/a><\/p>\n<p>This is the <a href=\"http:\/\/www.maybachusa.com\/index.php\" target=\"_blank\">Maybach<\/a> of DR solutions for virtualisation, and is priced as such.\u00a0 It is therefore well outside the reach of the SMB.\u00a0 The latency limitations with some solutions can eliminate some of the benefits.\u00a0 And it does require identical storage in both sites.\u00a0 That can be an issue with branch\/regional office to head office replication strategies, or using hosting company rental solutions.<\/p>\n<p>Now let\u2019s consider what 2012 may bring us, based purely on the couple of minutes presentation of Hyper-V replica that was at WPC11.<\/p>\n<p><strong><span style=\"text-decoration: underline;\">Hyper-V Replica Solution<\/span><\/strong><\/p>\n<p>I previously <a href=\"https:\/\/aidanfinn.com\/?p=11334\" target=\"_blank\">blogged<\/a> about the little bit of technology that was on show at WPC 2011, with a couple of screenshots that revealed functionality.<\/p>\n<p>Hyper-V Replica <em>appears <\/em>(in the demonstrated pre-beta build and things are subject to change) to offer:<\/p>\n<ul>\n<li>Scheduled replication, which can be based on VSS to maintain application\/database consistency (SQL, Exchange, etc).\u00a0 You can schedule the replication for outside core hours, minimizing the impact on your Internet link on normal business operations.<\/li>\n<li>Asynchronous replication.\u00a0 This is perfect for the SMB or the distant\/small regional\/branch office because it allows the use of lower priced connections, and allows replication over longer distances, e.g. cross-continent.<\/li>\n<li>You appear to be able to maintain several snapshots at the destination site.\u00a0 This <em>could<\/em> <em>possibly <\/em>cover you in the corruption scenario.<\/li>\n<li>The choice of authentication between replicating hosts appeared to allow Kerberos (in the same forest) and X.509 certificates.\u00a0 Maybe this would allow replication to a different forest: in other words a service provider where equipment or space would be rented?<\/li>\n<\/ul>\n<p>What Hyper-V Replica will give us is the ability to replicate VMs (and all their contents) from one site to another in a reliable and economic manner.\u00a0 It is asynchronous and that won\u2019t suit everyone \u2026 but those few who really need synchronous replication (NASDAQ and the like) don\u2019t have an issue buying two or three Hitachi SANs, or similar, at a time.<\/p>\n<p><a href=\"https:\/\/aidanfinn.com\/wp-content\/uploads\/2011\/07\/image16.png\"><img loading=\"lazy\" decoding=\"async\" style=\"background-image: none; padding-left: 0px; padding-right: 0px; display: block; float: none; margin-left: auto; margin-right: auto; padding-top: 0px; border: 0px;\" title=\"image\" src=\"https:\/\/aidanfinn.com\/wp-content\/uploads\/2011\/07\/image_thumb16.png\" border=\"0\" alt=\"image\" width=\"504\" height=\"223\" \/><\/a><\/p>\n<p>I reckon DPM and DPM replication still have a role in the Hyper-V Replica (or any replication)\u00a0scenario.\u00a0 If we do have the ability to keep snapshots, we\u2019ll only have a few of them.\u00a0 What do you do if you invoke your DR after losing the primary site (flood, fire, etc) and someone needs to restore a production database, or a file with important decision\/contract data?\u00a0 Are you going to call in your tapes from last week?\u00a0 Hah!\u00a0 I bet that courier is getting themselves and their family to safety, stuck in traffic (see post-9\/11 bridge closures or state of the roads in New Orleans floods), busy handling lots of similar requests, or worse (it was a disaster).\u00a0 Replicating your back to the secondary site will allow you restore data (that is still on the disk store) where required without relying on external services.<\/p>\n<p>Some people actually send their tapes to be stored at their DR site as their offsite archival.\u00a0 That would also help.\u00a0 However, remember you are invoking a DR plan because of an unexpected emergency or disaster.\u00a0 Things will not be going smoothly.\u00a0 Expect it to be the worst day of your career.\u00a0 I bet you\u2019ve had a few bad ones where things don\u2019t go well.\u00a0 Are you going to rely entirely on tape during this time frame?\u00a0 Your day will only get worse if you do: tapes are notoriously unreliable, especially when you need them most.\u00a0 Tapes are slow, and you may find a director impatiently mouth-breathing behind you as the tape catalogues on the backup server.\u00a0 And how often do you use that tape library in the DR site?<\/p>\n<p>To me, it seems like the best backup solution, in addition to Hyper-V Replica (a normal feature of the new version of Hyper-V that I cannot wait to start selling), is to combine quick\/reliable disk-disk-disk backup\/replication for short term backup along with tape for archival.<\/p>\n<p>That\u2019s my thinking now, after seeing just a few minutes of a pre-beta demo on a webcast.\u00a0 As I said, it\u2019s subject to change.\u00a0 We\u2019ll learn more at\/after Build in September and as we progress from beta-RC-RTM.\u00a0 Until then, these are musings, and not something to start strategising on.<\/p>\n<div id=\"scid:0767317B-992E-4b12-91E0-4F059A8CECA8:e24a10fc-4d56-4ac9-b724-a7e5054fb8be\" class=\"wlWriterEditableSmartContent\" style=\"margin: 0px; display: inline; float: none; padding: 0px;\">Technorati Tags: <a rel=\"tag\" href=\"http:\/\/technorati.com\/tags\/Hyper-V\">Hyper-V<\/a>,<a rel=\"tag\" href=\"http:\/\/technorati.com\/tags\/Virtualisation\">Virtualisation<\/a>,<a rel=\"tag\" href=\"http:\/\/technorati.com\/tags\/Windows+8\">Windows 8<\/a>,<a rel=\"tag\" href=\"http:\/\/technorati.com\/tags\/Backup\">Backup<\/a>,<a rel=\"tag\" href=\"http:\/\/technorati.com\/tags\/System+Center\">System Center<\/a>,<a rel=\"tag\" href=\"http:\/\/technorati.com\/tags\/DPM\">DPM<\/a><\/div>\n","protected":false},"excerpt":{"rendered":"<p>See my more recent post which talks in great detail about how Hyper-V Replica works and how to use it. At WPC11, Microsoft introduced (at a very high level) a new feature of Windows 8 (2012?) Server called Hyper-V Replica.\u00a0 This came up in conversation in meetings yesterday and I immediately thought that customers in &hellip; <a href=\"https:\/\/aidanfinn.com\/?p=11419\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Hyper-V Replica DR Strategy Musings VS What We Can Do Now&#8221;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","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":[55,175,181,193,195,109],"class_list":["post-11419","post","type-post","status-publish","format-standard","hentry","category-hyper-v","tag-backup","tag-dpm","tag-hyper-v","tag-system-center","tag-virtualisation","tag-windows-8"],"aioseo_notices":[],"jetpack_featured_media_url":"","amp_enabled":true,"_links":{"self":[{"href":"https:\/\/aidanfinn.com\/index.php?rest_route=\/wp\/v2\/posts\/11419","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=11419"}],"version-history":[{"count":0,"href":"https:\/\/aidanfinn.com\/index.php?rest_route=\/wp\/v2\/posts\/11419\/revisions"}],"wp:attachment":[{"href":"https:\/\/aidanfinn.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=11419"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/aidanfinn.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=11419"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/aidanfinn.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=11419"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}