Instead the server’s hard drives are also virtualized and set either on a Storage Attached Network (SAN) via FibreChannel or iSCSI, or mounted on a Network File System (NFS) volume on Network attached Storage (NAS). Unlike your standard desktop or standard physical server, the hard disk of a VMWare server is not generally located on a physical disk inside the server. The Storage Subsystem Plays the First Key Role When explaining how VMotion works, its not uncommon that I say to myself that “…it is quite amazing that as complicated is it is (and yet so elegantly simple) that it actually works.” There were definitely some big brains working at VMWare, and most of it can be attributed to Mike Nelson who led the VMotion project. So let’s move on to how VMotion actually works. So how does VMotion work? Let’s find out! How VMotion Works In the VMotion world, new hardware can be built and the virtual server moved without any downtime. Before this technology became commonplace in data centers, outage windows had to be negotiated with customers and servers had to be taken off-line for hours to replace or upgrade hardware. This has really changed how we handle system maintenance and outages in modern compute environments. Since a server can be moved to completely different hardware while it is running, without downtime the underlying hardware can be swapped out, or taken down for maintenance without the end-users or other applications being affected, or even knowing it has happened. There are some amazing benefits to VMotion and Live Migration. In fact, Microsoft has a similar technology in the Hyper-V stack known as, you guessed it: Hyper-V Live Migration. This technology is sometimes called “live migration”. VMotion is VMWare’s technology that enables a virtual computer to be moved from one physical host server to another, while it is running and with no interruption in service. So before we talk about how VMotion works, let’s quickly cover what it actually is! I still routinely run into people who have no idea that VMotion exists, and when they find out what it does they are always amazed that such a feat is even possible, much less practical! Since my project on building two 1U servers for ESXi, I’ve gotten a lot of question on “How does VMotion work?” You have to admit that VMWare created some really cool technology back in 2003 when they released VMotion.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |