Virtualization and Management Tool Topics 289
Other applications, such as Microsoft Exchange, may requirement run-
ning on block-based storage or on a Microsoft-based file system. Traditional
databases such as Oracle, Microsoft SQL, or IBM DB2/UDB have had a
preference and recommendation, if not requirement, to run on block-based
storage. Databases such as Oracle can and do run on NFS storage and, by
leveraging a feature in NFS V3 or later called direct I/O (DIO), can per-
form block-like access of NAS storage without having to read or write an
entire file. These rules and requirements are changing, and it is important to
consult with vendors or product specialists regarding specific guidelines and
recommendations.
9.6.2 Oversubscription: Not Just for ...