This illustration shows Oracle RAC on an extended distance cluster. The configuration shows three nodes at each of two different locations, Site A and Site B. Below each site an double-sided arrow links a disk drum labelled "Oracle RAC Database" to the site above it. Next to each database is a list that describes its main purposes, including: "Database Files (ASM)," "Oracle Cluster Registry (OCR)," and "Voting Disk." An arrow is located between the disk drums and it is labelled "ASM Mirroring" to indicate that ASM is used to mirror the database files.
In the center of the graphic above Sites A and B there is a simple box that represents a third site. The box contains this label: "Third Site for Voting Disk (Mounted via NFS or iSCSI)." All of the nodes are connected by a redundant public network, a redundant private network, and a redundant SAN. The public network and the SAN are configured on a wide area network (WAN).
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