HP 3PAR Windows 2012 and Windows Server 2008 Implementation Guide

Target Port Limits and Specifications
To avoid overwhelming a target port and ensure continuous I/O operations, observe the following
limitations on a target port:
• For information on the maximum number of supported host ports per HP 3PAR StoreServ
Storage port, consult the HP 3PAR Support Matrix on the HP SPOCK website:
HP SPOCK
• I/O queue depth on each HP 3PAR StoreServ Storage HBA model, as follows:
QLogic 1G: 512◦
◦ QLogic 10G: 2048 (HP 3PAR StoreServ 10000 and HP 3PAR StoreServ 7000 systems
only)
• The I/O queues are shared among the connected host HBA ports on a first-come, first-served
basis.
• When all queues are in use and a host HBA port tries to initiate I/O, it receives a target queue
full response from the HP 3PAR StoreServ Storage port. This condition can result in erratic I/O
performance on each host. If this condition occurs, each host should be throttled so that it
cannot overrun the HP 3PAR StoreServ Storage port's queues when all hosts are delivering
their maximum number of I/O requests.
HP 3PAR OS Persistent Ports
The HP 3PAR OS Persistent Ports (or virtual ports) feature minimizes I/O disruption during an
HP 3PAR StoreServ Storage online upgrade or node-down event (online upgrade, node reboot,
or cable pull test). Port shutdown or reset events do not trigger this feature.
Each iSCSI target storage array port has a partner array port automatically assigned by the system.
Partner ports are assigned across array node pairs.
HP 3PAR OS Persistent Ports allows an HP 3PAR StoreServ Storage iSCSI port to assume the identity
(port IP address) of a failed port while retaining its own identity. Where a given physical port
assumes the identity of its partner port, the assumed port is designated as a persistent port. Array
port failover and failback with HP 3PAR OS Persistent Ports is transparent to most host-based
multipathing software, which can keep all of its I/O paths active.
NOTE: Use of HP 3PAR OS Persistent Ports technology does not negate the need for properly
installed, configured, and maintained host multi-pathing software.
For a more complete description of the HP 3PAR OS Persistent Ports feature, its operation, and a
complete list of required setup and connectivity guidelines, see:
• the HP Technical white paper HP 3PAR StoreServ Persistent Ports (HP document
#F4AA4-4545ENW)
This document is available on the following HP SC website:
HP Support Center
• the HP 3PAR Command Line Interface Administrator’s Manual, “Using Persistent Ports for
Nondisruptive Online Software Upgrades”
This document is available on the following HP SC website:
HP Support Center
Target Port Limits and Specifications 55