The VMware vCenter Inventory Service is a caching component used to enhance vSphere Web Client responses
to queries by removing the performance tax associated with communicating directly against the already busy
core vCenter processes. Approximately 90 percent of all client requests are read-only queries. These include
retrieving configurations of objects, such as virtual machines in a cluster. Removing such operations from core
vCenter processing enables vCenter Server to provide better resource allocation for its ongoing operations,
including statistics management and service-level optimization.
TECHNICAL WHITE PAPER / 4
VMware vCenter Server 5.5
Deployment Guide
The vCenter Inventory Service also stores the object-tagging feature, introduced in vSphere 5.1. This feature
enables the inclusion of external metadata that can attach additional attributes. These attributes can then be
used to aid in retrieving criteria based on search requirements or organizational groupings. Tags are saved
directly to the vCenter Inventory Service cache, not to the vCenter database.
The vCenter Inventory Service is delivered as a file-level (xDB format) cache and can be read- and
write-intensive on the disk subsystem due to frequent updates and client queries.