HP 3PAR AIX and IBM Virtual I/O Server Implementation Guide

NOTE: The IBM Virtual I/O Server setting to enable dynamic tracking is recommended for
all fabric.
• 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
To avoid overwhelming a target port and ensure continuous I/O operations, observe the following
limitations on a target port:
• Maximum of 64 host server ports per HP 3PAR StoreServ Storage port, with a maximum total
of 1,024 host server ports per HP 3PAR StoreServ Storage.
• 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 server 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 server. If this condition occurs, each host server should be throttled
so that it can not overrun the HP 3PAR StoreServ Storage port's queues when all host servers
are delivering their maximum number of I/O requests.
NOTE: When host server 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 server 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 server 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 versions 3.1.2.MU2 is a more
efficient and dynamic solution from managing server workloads and can be utilized as an alternative
to setting host server 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 for using HP 3PAR Priority Optimization with QoS on the HP 3PAR StoreServ Storage array,
see the HP 3PAR Priority Optimization technical white paper on the HP Support Center:
HP 3PAR Priority Optimization
OS Specific Expected Behavior
As noted in the HP 3PAR Priority Optimization white paper, there is no limitation on the minimum
number of IOPS and/or Bandwidth that can be set on a given VVset QoS Rule. It is important
Setting Up and Zoning the Fabric 13