6.0.1

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Rules Based on Tags on page 229
Rules based on tags reference datastore tags that you associate with specic datastores. You can apply
more than one tag to a datastore.
Common Rules
Common rules are based on data services that are generic for all types of storage and do not depend on a
datastore. These additional services become available in the VM Storage Policies interface when you install
third-party I/O lters developed through vSphere APIs for I/O Filtering. You can reference these data
services in a VM storage policy.
Unlike storage-specic rules, common rules do not dene storage placement and storage requirements for a
virtual machine, but ensure that additional data services, such as I/O lters, become enabled for the virtual
machine. No maer which datastore the virtual machine runs on, the enabled lters can provide the
following services:
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Caching. Congures a cache for virtual disk data. The lter can use a local cache or a ash storage
device to cache the data and increase the Input/Output Operations Per Second and hardware utilization
rates for the virtual disk.
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Replication. Replicates virtual machine or virtual disks to external targets such as another host or
cluster.
For more information about I/O lters, see Chapter 21, “Filtering Virtual Machine I/O,” on page 243.
Rules Based on Storage-Specific Data Services
These rules are based on data services that storage entities such as Virtual SAN and Virtual Volumes
advertise.
To supply information about underlying storage to vCenter Server, Virtual SAN and Virtual Volumes use
storage providers, also called VASA providers. Storage information and datastore characteristics appear in
the VM Storage Policies interface of the vSphere Web Client as data services oered by the specic datastore
type.
A single datastore can oer multiple services. The data services are grouped in a datastore prole that
outlines the quality of service that the datastore can deliver.
When you create rules for a VM storage policy, you reference data services that a specic datastore
advertises. To the virtual machine that uses this policy, the datastore guarantees that it can satisfy the
storage requirements of the virtual machine. The datastore also can provide the virtual machine with a
specic set of characteristics for capacity, performance, availability, redundancy, and so on.
For more information about storage providers, see Chapter 25, “Using Storage Providers,” on page 277.
Rules Based on Tags
Rules based on tags reference datastore tags that you associate with specic datastores. You can apply more
than one tag to a datastore.
Typically, tags serve the following purposes:
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Aach a broad storage-level denition to datastores that are not represented by any storage providers,
for example, VMFS and NFS datastores.
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Encode policy-relevant information that is not advertised through vSphere API for Storage Awareness
(VASA), such as geographical location or administrative group.
Similar to storage-specic services, all tags associated with datastores appear in the VM Storage Policies
interface. You can use the tags when you dene rules for the storage policies.
Chapter 20 Virtual Machine Storage Policies
VMware, Inc. 229