The world is creating more and more data and needs it faster. Think about new software like Hadoop which is able to analyse data. Big data is a name for this.
Besides the need for lots of storage to store data, there is also a need to access data as fast as possible. Think VDI which needs a good performance to satisfy the enduser. We are seeing more and more the usage of Flash/SSD drives for VDI purposes in SAN solutions.
Another way to both satisfy the needs for performance and storage capacity is to use local storage and cache in the ESXi host. Local storage is is most cases faster than storage presented over networks. Using local storage is also much cheaper than shared storage. No switches, no cabling, no expensive SAN, licenses, etc
VMware vCloud Distributed Storage is a new virtual SAN technology presented first at VMworld 2012. It is not available yet but is a technology preview. It might never be released but I highly doubt that. This feature would be a candidate for vSphere 6.0
The Distributed Storage layer is built into the ESXi kernel. There is no virtual appliance doing the technology.It aggregates storage local to the server and exposes it as datastores to virtual machines. A mix of storage needs to be used: SSD/Flash for read/write and traditional harddisks for persistent storage.
Data can be replicated to another server to make the data available in case the server has failed. The technology will need 10Gbps for cluster communication/replication and Distributed Switch for Network I/O Control.
A distributed storage cluster needs at least 3 vSphere 5.1 nodes.
The feature will be named vSAN in the user interface and can be managed from the vSphere Web Client. I am not sure if it can be managed from the vSphere Infrastructure Client.
Some use cases for this technology are Big Data, VDI and Test/Dev infrastructure. It will not be a replacement of SAN/NAS obviously, but will fill a niche in the storage market.
VMware gave some more information on vSAN at VMworld in a breakout session named INF-STO2192 – Distributed Storage: Tech Preview Of a Virtual SAN Technology
Duncan Epping, employee of VMware and blogger at Yellow-Bricks wrote a great blogposting about what was presented in this session.
Massimo Re Ferre’ VMware vCloud Architect has a long posting titled VMware Distributed Storage – This is Where the (Cloud) World Collapses This post isn’t going to talk specifically about the VMware Distributed Storage technology. It is rather going to talk about the philosophy behind it and the trends in the industry.
Session EUC1305 had some information on Distributed Storage as well. See the slidedeck here. The session has been recorded as well, see it at Youtube.
Ray Lucchesi, President and Founder of Silverton Consulting has some info on VMware vision on storage in his blog titled
vSphere 5.1 storage enhancements and future vision
More info on myvirtualcloud
VMware Distributed Storage or VSAN