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What is VMware VAIO and why is it important?

VSphere APIs for I/O Filters, available with the next release of the hypervisor, lets third-party products access a VM's I/O stream to provide storage features.

VMware has had its vSphere APIs for I/O Filters in the works for quite some time, and according to the vendor,...

it will be one of the major new additions to its next release.

To be technically precise, vSphere APIs for I/O Filters (VAIO) isn't a feature, but rather a set of application programming interfaces (APIs) that will be made available to VMware partners. VMware VAIO will allow third-party vendors to develop applications that have direct access to a virtual machine's (VM) I/O stream. Vendors will be able to use this capability to develop all manner of storage products and capabilities for VMs. For instance, I eventually expect to see third-party deduplication, caching and encryption products that are built to leverage the API. But for now, VMware is restricting partners to two use cases for the filter. Partners will initially be allowed to develop filters for flash cache acceleration and replication. VMware plans to eventually allow the filters to be used for more general purposes.

The most interesting thing about this API is it allows a VM's raw I/O stream to be exposed through a filter. The filter takes the form of a vSphere Installation Bundle, which is associated with a specific VMDK file. At first, the filter's architecture might seem unimportant, but VMware chose to implement the filter in a very specific way.

Even though the filter must be installed on an ESXi host, it exists as a VM-level component, not a host-level component. This means that if a third-party filter were to cause a problem, it should not impact the host server. The problem should theoretically be isolated to the VM that is using the filter.

According to VMware, administrators will be able to enable filters through Storage Policy-Based Management. A single ESXi server can accommodate multiple filter types, and it will be up to the administrator to enable the filters for use with a VM. Incidentally, Storage Policy Based Management will also continue to be used for creating storage policies for virtual SANs.

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