Compaq 3200 Adding Storage Capacity, Bus Master Data Transfers, 18Understanding Drive Arrays

E-18Understanding Drive Arrays

Bus Master Data Transfers

The Smart Array 3200 Controller is a bus master device that takes control of the PCI bus during high-speed transfers. This allows the system processor to handle application processing or other types of tasks. Data transfer occurs at rates of up to 133 MB/sec for the PCI bus. Bus master high-speed transfers are particularly important when the supported models are used in conjunction with multiple expansion boards such as network interface controllers (NICs).

Adding Storage Capacity

Capacity expansion is increasing the size of an array by adding physical drives and creating additional logical drives. Capacity extension refers to increasing the size of an array by adding physical drives and increasing an existing logical drive without adding more logical drives.

The Smart Array 3200 Controller enables the configuration of one or more separate logical drives into a single drive array. The controller also supports extending the capacity of an existing logical drive. An existing drive array can be expanded by adding one or more logical drives to the array or by increasing the capacity of an existing logical drive. To create the room for the additional logical drives, more physical drives must be added. See Figure E-10.

Original

Logical

Drive

Added

Physical

Drives

Data from original logical drive redistributed over "Top" of all physical drives.

New logical drive created over "Bottom" of all physical drives or added capacity of the original logical drive.

Figure E-10. Beginning capacity expansion by adding more physical drives