vSAN Storage Policy Design for the Management Domain
After you enable and configure VMware vSAN in VMware Cloud Foundation, you can create
storage policies that define the virtual machine storage characteristics. Storage
characteristics specify different levels of service for different virtual machines.
Configure policies according to the business
requirements of the application. By using policies, vSAN can adjust the performance and the
availability of a disk on the fly.
Policy design starts with assessment of business needs and application requirements. Assess the use cases for VMware vSAN to determine the necessary policies. Start by assessing the following application requirements:
- I/O performance and profile of your workloads on a per-virtual-disk basis
- Working sets of your workloads
- Hot-add of additional cache (requires repopulation of cache)
- Specific application best practice (such as block size)
After assessment, configure the software-defined storage module policies for availability and performance in a conservative manner so that consumed space and recoverability are balanced. Usually the default system policy covers most common cases. You create custom policies if specific requirements for performance or availability exist.
If you do not specify a user-configured policy, vSAN uses a default system policy of 1 failure to tolerate and 1 disk stripe for virtual machine namespace and virtual disks. To ensure protection for critical virtual machine components, vSAN uses the policy set on virtual machine namespace for swap files. vSAN also uses the policy set on the virtual disk for the associated snapshot delta disks, if exist.
Object Type | Policy | Comments |
|---|---|---|
Virtual machine namespace | User-configured storage policy | Can be any storage policy configured on the system. |
Swap | Uses the virtual machine namespace
policy | Same as the virtual machine namespace
policy. |
Virtual disks | User-configured storage Policy | Can be any storage policy configured on the system. |
Virtual disk snapshots | Uses the virtual disk policy | Same as the virtual disk policy. |