I tried giving you a answer for this by typing but trust me its not a 1, 2,3 line answer so would ask you to refer the doc  EMC Clariion Storage system Fundamentals and Availability which can be found  in powerlink @  Home > Products > Hardware/Platforms > CLARiiON CX4 Series > White Papers  In this pdf start reading Chapter 8 from page 78.  You will understand this in minutes.  MIght help [IMAGE]  Thanks
Hi experts,  I have three questions regarding performance:  (1) I learned that for a 15k rpm FC drive, the rules of thumb for drive performance is IOPS = 180, bandwidth = 12MB/s. As i know, different I/O profile would make the drive deliver different result. Say if the workload is perfectly large sequential, the bandwidth may be doubled, even more, right?   (2) how is the above valued calculated and under what kind of I/O profile?   (3)  For I/O profile that is mostly [large, sequential], then the response time should be increased quickly. Let's say for CIFS copying, does it care about response time? Who determines the response time requirements? CIFS protocol itself or explorer.exe for Windows when doing file copy for example?  thank you!!
How is the rule of thumb of disk performance reference value calculated?