Interesting topic. The 3PAR implementation guide for ESX covers this, but I believe manually setting this is only for older versions ESX or older versions of 3PAR. The linked document seems quite thorough and includes ESX commands and scripts to help with setup.
http://bizsupport1.austin.hp.com/bc/doc ... 290624.pdfEach 8g port on the 10000 series has an I/O Queue Depth of 3276, and supports a max of 32 hosts.
(see Page 13)
As of VMware ESX server release 3.5 update 4, and including ESX 4.0, and ESXi 5.0, an algorithm has been added that allows ESX to respond to Queue Full and Busy SCSI messages from the storage array. The Queue Full or Busy response by ESX is to back off of I/O for a period of time, thus helping to prevent overdriving of the HP 3PAR StoreServ Storage ports. This feature should be enabled as part of an ESX - HP 3PAR StoreServ Storage deployment.
The Queue Full and Busy LUN-throttling algorithm is disabled by default. To enable the algorithm,
complete the following steps... (see the linked document)