6.5.1

Table Of Contents
Filtering Virtual Machine I/O 23
I/O filters are software components that can be installed on ESXi hosts and can offer additional data
services to virtual machines. The filters process I/O requests, which move between the guest operating
system of a virtual machine and virtual disks.
The I/O filters can be offered by VMware or created by third parties through vSphere APIs for I/O Filtering
(VAIO).
This chapter includes the following topics:
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About I/O Filters
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Using Flash Storage Devices with Cache I/O Filters
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System Requirements for I/O Filters
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Configure I/O Filters in the vSphere Environment
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Managing I/O Filters
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I/O Filter Guidelines and Best Practices
About I/O Filters
I/O filters can gain direct access to the virtual machine I/O path. You can enable the I/O filter for an
individual virtual disk level. The I/O filters are independent of the storage topology.
VMware offers certain categories of I/O filters. In addition, third-party vendors can create the I/O filters.
Typically, they are distributed as packages that provide an installer to deploy the filter components on
vCenter Server and ESXi host clusters.
After the I/O filters are deployed, vCenter Server configures and registers an I/O filter storage provider,
also called a VASA provider, for each host in the cluster. The storage providers communicate with
vCenter Server and make data services offered by the I/O filter visible in the VM Storage Policies
interface. You can reference these data services when defining common rules for a VM policy. After you
associate virtual disks with this policy, the I/O filters are enabled on the virtual disks.
Datastore Support
I/O filters can support all datastore types including the following:
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VMFS
VMware, Inc.
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