Performance Tuning - Dell Brocade VDX 6940 Configuration Manual

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Performance tuning

When testing the VDX 6940 and using 802.3x flow control (Tx off, Rx on), the default buffer allocation did not
yield optimal throughput and significant TCP retransmits were observed. The following section shows how to
configure the QoS receive buffer. Testing indicated the optimal setting is 3MB for the receive queue.
sw0# configure
sw0(config)# rbridge-id 1
sw0(config-rbridge-id-1)# qos rcv-queue limit 3000
sw0(config-rbridge-id-1)# end
sw0#
Note: Repeat the commands to configure the buffer on the second switch.
10 Brocade VDX 6940 Switch Configuration Guide for Dell PS Series SANs | SCG3306