Like any storage device the Exadata Storage Server is a computer with CPUs, memory, a bus, disks, NICs, and the other components normally found in a server. It also runs an operating system (OS), which in the case of Exadata is Oracle Linux. The Exadata Storage Server Software resident in the Exadata cell runs under OL with the Unbreakable Enterprise Kernel. OL is accessible in a restricted mode to administer and manage the Exadata cell.
CELLSRV (Cell Services) is the primary component of the Exadata software running in the cell and provides the majority of Exadata storage services. CELLSRV is multi-threaded software that communicates with the database instance on the database server, and serves blocks to databases based on the iDB protocol. It provides the advanced SQL offload capabilities, serves Oracle blocks when SQL offload processing is not possible, and implements the DBRM I/O resource management functionality to meter out I/O bandwidth to the various databases and consumer groups issuing I/O.
Two other components of Oracle software running in the cell are the Management Server (MS) and Restart Server (RS). The MS is the primary interface to administer, manage and query the status of the Exadata cell. It works in cooperation with the Exadata cell command line interface (CLI) and EM Exadata plug-in, and provides standalone Exadata cell management and configuration. For example, from the cell, CLI commands are issued to configure storage, query I/O statistics and restart the cell. Also supplied is a distributed CLI so commands can be sent to multiple cells to ease management across cells. Restart Server (RS) ensures the ongoing functioning of the Exadata software and services. It is used to update the Exadata software. It also ensures storage services are started and running and services are restarted when required.
