AX150SCi 'outstanding I/O per LUN' vaule?

Hello,

I am using an older EMC AX150SCi SAN to store multiple VMFS volumes shared between two ESXi 4.0 hosts. Each VMFS volume is stored on its own dedicated LUN (some LUNs are on dedicated 'disk pools' utilizing various RAID types). I am planning on upgrading the SAN in the near future but in the meantime I have a few questions regarding storage performance with the AX150SCi.

I know storage performance in ESXi relies on some optimized key components to perform efficiently, namely the kernel queue, HBA queue depth, ESX queue depth/LUN setting, the storage processor specs, etc. My question is regarding the SP; does the AX150SCi have a maximum 'outstanding I/O per LUN’ value? I know some SANs have a maximum outstanding I/O per LUN vaule of 256 for example... If not, how does the SP on the AX150SCi distribute the I/O requests between each LUN? Does it rely solely on the write cache and the individual disk I/O (IOPS)? Am I even asking the right question here?

Thanks,

Steve