Specifications

184 en | Implementations for AV Applications SCSI to SATA RAID Subsystem | Administrator’s Manual
F.01U.027.802 | V1 | 2006.11 Bosch Security Systems
13 Implementations for AV Applications
This chapter introduces some new firmware functions for AV applications. More options will
be available for AV applications with future firmware releases.
13.1 Maximum Drive Response Time
In situations such as drive failure or the occurrence of media error, a read or write action
returned after several hundreds milliseconds would prove too long and cause choppy audio or
dropped video frames.
The maximum response time option, as displayed below, provides a timeout value for process-
ing read/write requests. If timeout is reported on a specific member of an array, the sub-
system immediately retrieves data from the parity data and other members of the array. In this
way, causes of delay can be eliminated.
Fig. 13.1 Selecting Maximum Drive Response Timeout Value
To prepare the array for read-intensive applications, the following are recommended:
1. Performance using the write-through caching mode is better than that using the write-
back mode on subsystems equipped with redundant RAID controllers.
2. Arrays should not be partitioned.
3. The priorities for Rebuild or Add-drive operations should be set to “low.”
4. Another timeout value, the “Drive I/O Timeout” which determines whether a drive has
eventually failed to respond to I/O requests, is required as the first-level timeout.
i
NOTICE!
All figures in this chapter are showing examples using the management hyper terminal screen.