6.7

About Rules and Rule Sets
After the VM Storage Policies interface is populated with the appropriate data, you can start creating your
storage policies. Creating a policy involves defining specific storage placement rules and rules to
configure data services.
Rules The rule is a basic element of the VM storage policy. Each individual rule is
a statement that describes a single requirement for virtual machine storage
and data services.
Rule Sets Within a storage policy, individual rules are organized into collections of
rules, or rule sets. Typically, the rule sets can be in one of the following
categories: rules for host-based services and datastore-specific rules.
Datastore-Specific Rule
Sets
Each rule set must include placement rules that describe requirements for
virtual machine storage resources. All placement rules within a single rule
set represent a single storage entity. These rules can be based on storage
capabilities or tags.
In addition, the datastore-specific rule set can include optional rules or
storage policy components that describe data services to provide for the
virtual machine. Generally, these rules request such services as caching,
replication, other services provided by storage systems.
To define the storage policy, one datastore-specific set is required.
Additional rule sets are optional. A single policy can use multiple sets of
rules to define alternative storage placement parameters, often from
several storage providers.
Placement Rules:
Capability-Based
Placement rules specify a particular storage requirement for the VM and
enable SPBM to distinguish compatible datastores among all datastores in
the inventory. These rules also describe how the virtual machine storage
objects are allocated within the datastore to receive the required level of
service. For example, the rules can list Virtual Volumes as a destination and
define the maximum recovery point objective (RPO) for the Virtual Volumes
objects.
When you provision the virtual machine, these rules guide the decision that
SPBM makes about the virtual machine placement. SPBM finds the Virtual
Volumes datastores that can match the rules and satisfy the storage
requirements of the virtual machine. See Create a VM Storage Policy for
Virtual Volumes.
vSphere Storage
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