HP 3PAR RedHat and Oracle Linux Implementation Guide

In addition, some HP switches, such as the HP SN8000B 8-slot SAN backbone director switch,
the HP SN8000B 4-slot SAN director switch, the HP SN6000B 16 Gb FC switch, or the HP
SN3000B 16 Gb FC switch automatically select the proper fill-word mode 3 as the default
setting.
• McDATA switch or director ports should be in their default modes as G or GX-port (depending
on the switch model), with their speed setting permitting them to autonegotiate.
• Cisco switch ports that connect to HP 3PAR StoreServ Storage ports or host HBA ports should
be set to AdminMode = FX and AdminSpeed = auto port, with the speed set to auto negotiate.
• QLogic switch ports should be set to port type GL-port and port speed auto-detect. QLogic
switch ports that connect to the HP 3PAR StoreServ Storage should be set to I/O Stream Guard
disable or auto, but never enable.
Target Port Limits and Specifications for FC
To avoid overwhelming a target port and ensure continuous I/O operations, observe the following
limitations on a target port:
• See the HP 3PAR Support Matrix at the HP SPOCK website and adhere to the maximum
number of initiator connection supported per array port, per array node pair, and per array:
HP SPOCK
• I/O queue depth on each HP 3PAR StoreServ Storage HBA model, as follows:
QLogic 2G: 497◦
◦ LSI 2G: 510
◦ Emulex 4G: 959
◦ HP 3PAR HBA 4G: 1638
◦ HP 3PAR HBA 8G: 3276 (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.
NOTE: When host ports can access multiple targets on fabric zones, the assigned target
number assigned by the host driver for each discovered target can change when the host is
booted and some targets are not present in the zone. This situation may change the device
node access point for devices during a host reboot. This issue can occur with any
fabric-connected storage, and is not specific to the HP 3PAR StoreServ Storage.
HP 3PAR Priority Optimization
The HP 3PAR Priority Optimization feature introduced in HP 3PAR OS 3.1.2. MU2 is a more
efficient and dynamic solution for managing server workloads and can be utilized as an alternative
to setting host I/O throttles. Using this feature, a storage administrator is able to share storage
resources more effectively by enforcing quality of service limits on the array. No special settings
are needed on the host side to obtain the benefit of priority optimization although certain per target
or per adapter throttle settings may need to be adjusted in rare cases. For complete details about
how to use HP 3PAR Priority Optimization (Quality of Service) on HP 3PAR StoreServ Storage
16 Configuring the HP 3PAR StoreServ Storage for Fibre Channel