{"id":12435,"date":"2012-04-19T17:51:14","date_gmt":"2012-04-19T16:51:14","guid":{"rendered":"https:\/\/aidanfinn.com\/?p=12435"},"modified":"2012-04-19T17:51:14","modified_gmt":"2012-04-19T16:51:14","slug":"elias-khnaser-honorary-vmlimited-ambassador-talks-about-shared-nothing-live-migration","status":"publish","type":"post","link":"https:\/\/aidanfinn.com\/?p=12435","title":{"rendered":"Elias Khnaser, Honorary vmLimited Ambassador, Talks About Shared Nothing Live Migration"},"content":{"rendered":"

Back in 2009, Elias Khnaser posted a very badly informed article on InformationWeek with on why you shouldn\u2019t deploy Hyper-V.  I gave it a good bashing<\/a>, tearing down his points one by one with actual facts.  Well, just in time to be hired by Tad<\/a>, Elias is back and at it again<\/a>!<\/p>\n

First off, let\u2019s look at the title of the article:<\/p>\n

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Shared-Nothing Live Migration: Cool, But Not a Game-Changer<\/font><\/h5>\n<\/blockquote>\n

Hmm, I have to disagree.  No one else does this right now and it\u2019s a real problem for some.  Think of a large data centre going through a hardware or network refresh.  They can\u2019t afford down time while the export, carry, and import VMs.  They want to be able to move those VMs with the minimum of downtime, and maybe even eliminate downtime.  Shared Nothing Live Migration achieves this.<\/p>\n

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\u2026 entertain this scenario for me: a VM with 1 TB virtual disk … wait, Eli, you are not realistic, you might be thinking … fair enough — what about a VM with 500GB virtual disks? Moving that amount of data over a 1 GB Ethernet or even a 10 GB Ethernet is not quick or feasible in most environments \u2026<\/p>\n<\/blockquote>\n

Firstly, the vast<\/em> majority of VMs are small.  And while Windows Server 2012 Hyper-V can support 64 TB VHDX, they will the tiny minority.  And to be honest, not only will these size VMs be few and far between, but I\u2019d expect them to run on clustered hosts with shared storage so Share Nothing Live Migration wouldn\u2019t be needed \u2026 except for well planned and scheduled migrations to another part of the data centre.<\/p>\n

If you do have lots of 1 TB VMs to move around, then you\u2019re a very large data centre and you\u2019ll have lots of budget for big networking such as Infiniband with RDMA to speed things along.  For the rest of us:<\/p>\n