HP Cisco MDS 9120 Cisco MDS 9000 Family Fabric Manager Configuration Guide, Re - Page 1242

Example Configuration Chapter 66 Configuring Fabric Congestion Control and QoS Send documentation comments to [email protected] Step 4 Click the Apply Changes icon to save your changes. Example Configuration This section describes a configuration example for the application illustrated in Figure 66-7. Figure 66-7 Example Application for Traffic Prioritization OLTP server 21:00:00:0c:50:02:ca:b5 Disk 22:00:00:04:cf:22:eb:dc FC Congestion Backup server VOQ(s) Absolute VOQ(s) Absolute 21:00:00:0c:50:02:c7:ff High Medium Low High Medium Low 130667 Switch 1 Switch 2 Both the OLTP server and the backup server are accessing the disk. The backup server is writing large amounts of data to the disk. This data does not require specific service guarantees. The volumes of data generated by the OLTP server to the disk are comparatively much lower but this traffic requires faster response because transaction processing is a low latency application. The point of congestion is the link between Switch 2 and the disk, for traffic from the switch to the disk. The return path is largely uncongested as there is little backup traffic on this path. Service differentiation is needed at Switch 2 to prioritize the OLTP-server-to-disk traffic higher than the backup-server-to-disk traffic. To configure traffic prioritization for the example application, follow these steps: Step 1 Step 2 Step 3 Step 4 Step 5 Create the class maps. Create the policy map. Assign the service policy. Assign the weights for the DWRR queues. Repeat Step 1 through Step 4 on Switch 1 to address forward path congestion at both switches. Congestion could occur anywhere in the example configuration. To address congestion of the return path at both switches, you need to create two more class maps and include them in the policy map as follows: 66-10 Cisco MDS 9000 Family CLI Configuration Guide OL-16184-01, Cisco MDS SAN-OS Release 3.x