HP A7533A HP StorageWorks Fabric OS 5.X Procedures User Guide (AA-RVHWB-TE, Se - Page 97
Routing traffic, About data routing and routing policies, Specifying the routing policy
UPC - 829160830858
View all HP A7533A manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 97 highlights
6 Routing traffic This chapter describes HP StorageWorks switch routing features and procedures. About data routing and routing policies Data moves through a fabric from switch to switch and from storage to server along one or more paths that make up a route. Routing policies determine the correct path for each frame of data. CAUTION: For most configurations, the default routing policy is optimal, and provides the best performance. Change the policy only if there is a performance issue that is of concern, or a particular fabric configuration requires it. The following routing policies are available to tune routing performance: • Exchange-based routing: The choice of routing path is based on the source ID (SID), destination ID (DID), and Fibre Channel originator exchange ID (OXID), optimizing path utilization for the best performance. Thus, every exchange can take a different path through the fabric • Device-based routing: The choice of routing path is based on the Fibre Channel addresses of the SID and the DID, improving path utilization for better performance. Thus, the same route is always used and the sequence of exchanges is guaranteed. • Port-based routing: The choice of routing path is based only on the incoming port and the destination domain. To optimize port-based routing, the Dynamic Load Sharing feature (DLS) can be enabled to balance the load across the available output ports within a domain. Device-based and exchange-based routing require the use of DLS; when these policies are in effect, you cannot disable the DLS feature. Using port-based routing, you can assign a static route, in which the path chosen for traffic never changes. In contrast, device-based and exchange-based routing policies always employ dynamic path selection. Port-based routing is supported by all HP StorageWorks models (except the 4/256 SAN Director using configuration option 5; see Table 17 on page 91). Specifying the routing policy The following routing policies are supported: • Port-based path selection: The default on SAN Switch 2/8V, SAN Switch 2/16V, and SAN Switch 2/32, Core Switch 2/64, SAN Director 2/128, and 4/256 SAN Director (using configuration options 1 through 4). These switches support the port-based policy only; you cannot change the routing policy for these switches. The 4/8 SAN Switch, 4/16 SAN Switch, 4Gb SAN Switch for HP p-Class BladeSystem, and SAN Switch 4/32 can also use port-based routing. • Device-based path selection: Available on 4/8 SAN Switch, 4/16 SAN Switch, Brocade 4Gb SAN Switch for HP p-Class BladeSystem, and SAN Switch 4/32, and 4/256 SAN Director (using configuration option 5). If there are devices in your fabric that cannot accommodate out-of-order exchanges, use the device-based policy. In FICON environments device-based routing is recommended. • Exchange-based path selection: The default on the 4/8 SAN Switch, 4/16 SAN Switch, Brocade 4Gb SAN Switch for HP p-Class BladeSystem, and SAN Switch 4/32, and 4/256 SAN Director (using configuration option 5). See "Configuring Core Switch 2/64, SAN Director 2/128, and 4/256 SAN Director" on page 87 for details about 4/256 SAN Director configuration options. You can use the aptPolicy command to display and specify a different routing policy. Note that if you attempt to set the policy when the 4/256 SAN Director uses configuration options 1-4, an error message is returned. See the HP StorageWorks Fabric OS 5.x command reference guide for details on the aptPolicy command. Fabric OS 5.x administrator guide 97