HP StorageWorks 8/80 HP StorageWorks Fabric OS 6.2 administrator guide (5697-0 - Page 364

The switch automatically sets the priority for the host,target pairs specified in the zones based on the priority level in the zone name. NOTE: QoS can be used for device pairs that exist within the same fabric only. QoS priority information is not passed over EX_ or VEX_Ports and should not be used for devices in separate fabrics. If a QoS zone name prefix is specified in an LSAN zone (a zone beginning with prefix LSAN_), the QoS tag is ignored. Only the first prefix in a zone name is recognized. For example, a zone with the name LSAN_QOSH_zone1 is recognized as an LSAN zone and not a QoS zone. For example, Figure 56 shows a fabric with two hosts (H1, H2) and three targets (S1, S2, S3). The traffic prioritization is as follows: • Traffic between H1 and S1 is high priority. • Traffic between H1 and S3 and between H2 and S3 is low priority. • All other traffic is medium priority, which is the default. H1 Domain 1 Domain 3 S1 1 9 H2 14 3 13 12 S2 15 = Low priority 87 = Medium priority = High priority 16 S3 Domain 2 Figure 56 QoS traffic prioritization Domain 4 For this fabric, you could set up the following QoS zones: QOSH_Zone1Members: H1, S1 QOSL_Zone3Members: H1, H2, S3 QoS on E_Ports In addition to configuring the hosts and targets in a zone, you must also enable QoS on individual E_Ports that might carry traffic between the given host and target pairs. Path selection between the host,target pairs is governed by FSPF rules and is not affected by QoS priorities. By default, QoS is enabled on E_Ports in port configuration. For example, in Figure 57, QoS should be enabled on the encircled E_Ports. 362 Optimizing fabric behavior