To answer this question, let’s go on a comprehensive tour of the Oracle Exadata Database Machine. Oracle Exadata comes in a rack with the following hardware components that make up its database infrastructure: disks, servers, and networking gear. Oracle offers three configurations of its Exadata database machine: full rack, half rack, or quarter rack. The architecture is the same across all three types; however, the number of components in each differs.
To begin with, let’s look at Oracle Exadata’s full rack setup and dive into each of its components and the role they play.
- Database Nodes – The Exadata Database Machine runs Oracle Database 11g RAC (or Real Application Cluster). The cluster and database run on servers known as database nodes, compute nodes, or more often than not simply “nodes”. A full rack Exadata Database Machine has eight nodes running either Oracle Linux or Oracle Solaris.
- Storage Cells – Different from the normal direct attached storage case, the Exadata disks are not attached right to the database compute nodes but rather to a different server known as the storage cell or simply the “cell”. There are 14 cells in the full rack configuration. It is in these cells that the Oracle Exadata Server Software runs on top of Exadata’s Operating System.
- Disks – Each of the aforementioned cells have 12 disks. Depending on the Exadata Database Machine configuration, these disks are either 600GB high performance or 2TB high capacity. The customer selects the disk type at purchase.
- Flash Disks – In addition to the disks mentioned above, each cell also has 384GB of flash disks. These flash disks can be accessable to the compute nodes as storage or used as a secondary cache for the database cluster.
- Infiniband Circuitry – The cells and nodes are connected through infiniband in order to provide speed and low latency. The Exadata Database Machine has three infiniband switches for increased redundancy.
- Ethernet Switch – Businesses can communicate with the Exadata Database via infiniband or by Ethernet through a set of Ethernet switches with ports open to the outside. This allows clients to connect to the Exadata Database Machine nodes over Ethernet. DMAs connect to the nodes and cells using Ethernet as well. While Exadata system backups are recommended to be used via infiniband, they can be done over the network as well.
- KVM Switch – Oracle’s Exadata also consists of a keyboard, video, and mouse switch in order to provide direct access to its nodes and cells. This switch is used while setting up as well as when the network is unavailable. The KVM switch is a useful feature when working with Oracle Exadata support. Under normal operating conditions, however, the user will not need to go near the rack and use this KVM – not even for powering on and off the cells and nodes.
Now that you know the components, look at the next section to get a detailed description of the current generation Exadata components.
As of the publication of this article, the current generation of the Oracle Exadata Database Machine comes in two models (X2-2 and X2-8); three sizes (full rack, half rack, and quarter rack); as well as three classes of storage (high performance, high capacity SAS, and high capacity SATA).
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Next time, we will look at the software side of what makes the Oracle Exadata Database Machine tick.