vSAN requires that the virtual machines deployed on the vSAN datastores are assigned at least one storage policy.  When provisioning a virtual machine, if you do not explicitly assign a storage policy to the virtual machine, a generic system defined storage policy, called the vSAN Default Storage Policy, is applied to the virtual machine.

The default policy contains vSAN rulesets and a set of basic storage capabilities, typically used for the placement of virtual machines deployed on vSAN datastores.

Here is a list of the VxRail specifications for the vSAN Default Storage Policy in a live production environment.

• Number of failures to tolerate is set to 1.
• Number of disk stripes per object is set to 1.
• Flash read cache reservation or the flash capacity used for read cache is set to zero.
• Object space reservation is set to zero.  Setting the Object space reservation to zero means that the virtual disk will be thin provisioned, by default.
• Force Provisioning is set to No.

Let's take a look at how to view the current Storage Policies.

This part of the lab is presented as a Hands-on Labs Interactive Simulation. This will allow you to experience steps which are too time-consuming or resource intensive to do live in the lab environment. In this simulation, you can use the software interface as if you are interacting with a live environment.

The orange boxes show where to click, and the left and right arrow keys can also be used to move through the simulation in either direction.

1. Click Home.
2. Click Policies and Profiles.
3. Click VM Storage Policies.
4. Click the icon to Create a new VM Storage Policy.
5. The Name and Description of the new VM Storage Policy is already entered. Click Next.
6. Click Next.
7. Click None.
8. Rules will be based on vSAN. Click VSAN and Add Rule.
9. There are several options for Rules based on data services. We will Select Number of Disk Stripes per Object.
10. Enter 2 for the Number of disk stripes per object.
11. Click Next.

The VM Storage Policy is based on data services published by vSAN. The Rule you are adding changes the number of disk stripes per object.  Striping splits the data of a given object into multiple stripes, also known as segments:

• Each stripe is accessed simultaneously, potentially increasing performance in hybrid configurations.
• vSAN allows for up to 12-way striping.
• In most configurations, a strip width of 1 is sufficient.
• Stripes are distributed across multiple drives but not necessarily multiple hosts.
• Striping can limit object placement in smaller configurations.

11. Click Next.

12. Click Next.

13. Click Finish.

14. Click the name of the newly created VM Storage Policy VxRail vSAN STRIPE-2. This is a brand new policy as you created tailored to your requirements.  A VM will not use this policy until it is specifically applied to the VM.  

15. Click Home menu icon.

16. Switch to the VM and Templates view.

17. Locate the VM entitled Demo-VM.

18. Click the window to scroll down to verify compliance the Virtual Machine has with the VM Storage Policies.

19.  Right click Demo-VM and select VM Polices >>  Edit VM Storage Policies.

20.  Modify the Demo-VM to use a the newly created VM Storage Policy VxRail-vSAN-STRIPE-2.

The new VM Storage Policy Rule created "VxRail-vSAN-STRIPE-2".  The new policy is added to the list.

This policy can be applied to a virtual machine and its virtual disks. Virtual SAN will place the virtual machine objects in accordance with the requirements specified in the policy. For information about applying the storage policies to virtual machine objects, see the vSphere Performance Best Practices documentation located here.

20. Click Apply to All

21. Click OK

22. Click Check Compliance

Notice the VM Storage Policy has changed. The Virtual Machine is now compliant to the Storage Policy that is assigned to it.

Please proceed to the Conclusion of Module 4.

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