What is queue length?

[Luca Gabrielli]

Hello

I have some problem to define the Queue Lenghts over 1, 5, 15 minutes .
Someone can explain this concept to me?

Luca

[Uwe Zessin]

Well, as you have written in the disk array forum, I guess you are talking about the Queue Length or Queue Depth of a SCSI disk.

The SCSI protocoll allows an initiator (the server) to send multiple commands to a target (the disk or storage array) without waiting for completion of the first command. This allows the disk/array to optimize the data access by minimizing head moves.

Of course, you can send only so many commands to a device, because handling many outstanding commands requires
-- ressources on the server and
-- the storage device