In this post, the VSAN capabilities are examined in detail. These capabilities, which are surfaced by the VASA storage provider when the cluster is configured successfully, are used to set the availability, capacity & performance policies on a per VM basis when that VM is deployed on the vsanDatastore. There are 5 capabilities in the initial release of VSAN, as shown below. I will also try to highlight where you should use a non-default value for these capabilities.
The creation of a VSAN cluster is identical in many respects to how a vSphere administrator might create a DRS or vSphere HA cluster. A cluster object is created in the vCenter inventory, and one can either choose to enable the VSAN cluster functionality and then add in the hosts to the cluster, or add the hosts first, and then enable VSAN. When you enable the VSAN functionality on the cluster, a single option is displayed asking the administrator to choose a manual or automatic (default) cluster. This simply refers to whether the vSphere administrator would like VSAN to discover…
VASA, originally introduced in vSphere 5.0, are an extension of the vSphere Storage APIs. VASA is shorthand for vSphere Storage APIs for Storage Awareness. It initially allowed storage arrays to integrate with vCenter for management functionality via server-side plug-ins or Vendor Providers. The storage provider exists on either the storage array service processor or it may also be a standalone host – this is at the discretion of the vendor. In the case of VSAN, it also uses VASA, but interestingly the storage provider is now placed on the ESXi host. Read on to learn more.
One of the most important concepts to understand in VSAN, in my opinion, is the notion of storage objects and components. Virtual Machines deployed on a vsanDatastore on VSAN 5.5 may have 4 different kinds of storage objects associated with it: The Virtual Machine home or “namespace directory” A swap object (if the virtual machine is powered on) Virtual disks/VMDKs Delta-disks created for snapshots. Each delta-disk is an object. [Update: Additional objects types were introduced in later versions of VSAN, but these were the objects in VSAN 5.5]
I’ve actually had to change the order of VSAN posts just to make this very point – VSAN is NOT a Virtual Storage Appliance. I’ve seen multiple conversations on twitter, and some blog posts, which are completely inaccurate when it comes to this point. VSAN is completely and fully integrated into vSphere. There are no appliances to push down and no additional VIBs to install on ESXi version 5.5 and vCenter 5.5 – VSAN is built into vSphere as kernel modules. Now, Frank Denneman wrote an excellent article explaining the advantages of kernel modules over appliances here. I’d suggest reading…
This post contains the list of items you will need to get started with VSAN. I’ll also try to highlight some best practices when it comes to configuring VSAN. First off, lets start with the software requirements – those are the easy bits. You will need ESXi version 5.5 and vCenter server version 5.5. The vCenter server can be either the Windows version or the appliance version; both support VSAN. Finally you will need to familiarize yourself with the vSphere web client if you haven’t already done so. VSAN can only be managed from the vSphere web client; it is…
At last, VSAN is launched. Over the coming weeks and months, I plan on doing a series of VSAN (or Virtual SAN to be more accurate) posts. I will start with a brief introduction to the product which was announced at VMworld 2013 with a public beta.