Reducing the Number of Operational VLs in the Subnet in OpenSM


When streaming aggregation is enabled, it is recommended to reduce the number of enabled VLs in the subnet to 2 VLs.

To reduce the number of VLs, max_op_vl parameter of OpenSM has to be set according to required number of VLs. For example, configure OpenSM to enable 2 VLs in the subnet by changing the max_op_vl parameter in the OpenSM configuration file:


# Limit the maximal operational VLs max_op_vls 2

By default, for maximal performance, NVIDIA Quantum switches support single SHARP streaming aggregation flow.

To enable two simultaneous SHARP streaming aggregation flows, please contact Support.

Disabling SHARP on a specific network switch device can be performed using OpenSM device configuration file by performing the following:

  1. Define a port group with the specified network device in the port groups file. The group is specified by the pgrp_policy_file parameter in the OpenSM configuration file.
    For example:


    port-group name: NON_SHARP_SWITCHES port-guid: 0x0002c90000000001 end-port-group

  2. Configure OpenSM to disable SHARP on the devices of the specified port groups in device configuration file specified by the device_configuration_file parameter in OpenSM configuration file.


    port-conf port-group-name: NON_SHARP_SWITCHES sharp-enabled: 0 end-port-conf

  3. Reload OpenSM.

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