HP Compaq Integrated Smart Array Controller User Manual
Page 117
Understanding Drive Arrays B-11
Compaq Confidential – Need to Know Required
Writer: CDresden Project: Compaq Integrated Smart Array Controller User Guide Comments:
Part Number: 153236-001 File Name: i-appb Understanding Drive Arrays.doc Last Saved On: 8/27/99 11:35 AM
Concurrent I/O Request Servicing
The Integrated Smart Array Controller has the capability to service hundreds
of I/O requests at a time. For example, if you request data that resides on the
first drive and another user requests data that resides on the second drive, the
controller can deliver both pieces of information concurrently. The following
figure illustrates concurrent request servicing.
User 1
Request
User 2
Request
User 3
Request
User 4
Request
Figure B-8. Concurrent request servicing handles several I/O requests
Optimized Request Management
Optimized request management, also known as elevator trend sorting, is
another performance enhancement feature provided by the Integrated Smart
Array Controller. The controller receives and queues multiple data requests
from the operating system. The controller then rearranges the requests in an
order that optimizes performance.
To illustrate this concept, imagine the Integrated Smart Array Controller
receives a request for a physical drive that is not currently active. The
controller schedules the request immediately ahead of previously received
requests already queued to other active drives within the array. This request
management process operates concurrently with drive operations. The benefits
of optimized request management increase as greater demands are made on the
drive subsystem.