6.0.1

Table Of Contents
Filtering Virtual Machine I/O 21
vSphere APIs for I/O Filtering (VAIO) provide a framework that allows third parties to create software
components called I/O lters.
The lters can be installed on ESXi hosts and can oer additional data services to virtual machines by
processing I/O requests that move between the guest operating system of a virtual machine and virtual
disks.
This chapter includes the following topics:
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About I/O Filters,” on page 243
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“Using Flash Storage Devices with Cache I/O Filters,” on page 246
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“Deploy and Congure I/O Filters in the vSphere Environment,” on page 247
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“Managing I/O Filters,” on page 251
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“I/O Filter Guidelines and Best Practices,” on page 252
About I/O Filters
I/O lters that are associated with virtual disks gain direct access to the virtual machine I/O path regardless
of the underlying storage topology.
The I/O lters are created by third-party vendors and are distributed as packages that provide an installer to
deploy lter components on vCenter Server and ESXi host clusters.
After you install the I/O lter and deploy its components on the ESXi cluster, vCenter Server automatically
congures and registers an I/O lter storage provider, also called a VASA provider, for each host in the
cluster. The storage providers communicate with vCenter Server and make data services oered by the I/O
lter visible in the VM Storage Policies interface. You can reference these data services when creating
common rules for a VM policy. After you associate virtual disks with this policy, the I/O lters are enabled
on the virtual disks.
Types of I/O Filters
Typically, I/O lters are created by VMware partners through the vSphere APIs for I/O Filtering (VAIO)
developer program. Third-party vendors can develop I/O lters for multiple purposes.
In this release, the supported types of lters include the following:
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Caching. Implements a cache for virtual disk data. The lter can use a local ash storage device to cache
the data and increase the IOPS and hardware utilization rates for the virtual disk. If you use the caching
lter, you might need to congure a Virtual Flash Resource.
VMware, Inc.
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