AV¶

AV Displays information about the Audio/Visual settings.

This command is used to change the Audio/Visual configuration settings for the system. These parameters are used to tune the system and the disks for better performance and a lower latency. The writeback and prefetch settings for each LUN are changed with the CACHE command.

FAILCC=ON|OFF: This parameter will tell the host ports to report a check condition for all SCSI commands when the unit is in a failed state. This command should only be used in AV environments when a check condition is required instead of taking the unit off the loop. Default is OFF.
FASTAV=ON|OFF: This parameter enables and disables the disk fast Audio/Video read option for streaming data. If the FASTAV parameter is ON, the system will start the data transfer for read operations before all of the disk commands have finished. This feature reduces the latency for read operations but the system will be unable to check the integrity of the data. The FASTAVTIMEOUT parameter indicates how long the host command must wait before the FASTAV mechanism will activate. Note: This parameter is saved on a per-LUN basis. Use in combination with the LUN=x parameter to change the settings for a single LUN. Default is OFF.
FASTAVTIMEOUT=x: This parameter sets the timeout before the FASTAV option will activate on a host read command. The FASTAV mechanism will not be used until the host command takes longer than the timeout value. A value of zero indicates that the system will start the data transfer as soon as a minimum number of drives are ready. This value is in 100 millisecond increments. The range for ‘x’ is 0 to 600. The default is 200.
LUN=x: This parameter may be used in combination with the FAST_AV and RC parameters, in order to specify which LUN is to be changed. By default, if no LUN is specified with this parameter, then all the LUNs in the system will be updated . Valid LUNs are 0 to 127. Default is all LUNs.
ORDEREDQUEUE=x: Enables the use of ordered tags when communicating with the drives. The value ‘x’, indicates the number of disk commands that can be sent before an ordered tag must be sent to the disks: 0 indicates no ordered tags, 1 indicates every command has an ordered tag, 2 indicates every second command has an ordered tag, 3 indicates every third command has an ordered tag, 4 indicates every fourth command has an ordered tag, etc... Valid range is 0 to 255. Default is 0.
RC=ON|OFF: This parameter enables and disables the Read Continuous option for Audio/Video streaming data. If the RC parameter is ON, the system will start the data transfer for read operations after RCTIMEOUT is reached even if the disks commands have not finished. This feature is used to reduce the latency for read operations in Audio/Visual environments where latency is more important than data integrity. WARNING: This feature allows the system to return invalid data to the initiator. Note: This parameter is saved on a per-LUN basis. Use in combination with the LUN=x parameter to change the settings for a single LUN. Enabling this feature will automatically enable FASTAV. Default is OFF.
RCTIMEOUT=x: This parameter sets the host command timeout for the Read Continuous option for Audio/Video streaming data. A timeout value of zero will disable the Read Continuous feature in the system. This value is in 100 millisecond increments. The range for ‘x’ is 0 to 255. The default is 250.
UA=ON|OFF: This parameter enables and disables the initial Unit Attention condition when an initiator logs into the system. If the UA parameter is ON, the system will report a Unit Attention condition on the first SCSI command after the initiator logs in. If the UA parameter is OFF, the system will automatically clear the unit attention condition when an initiator logs in. Default is ON.