The Metadata Network

As with any client/server protocol, SNFS performance is subject to the limitations of the underlying network. Therefore, it is recommended that you use a dedicated Metadata Network to avoid contention with other network traffic. Neither TCP offload nor jumbo frames are required.

It is best practice to have all SNFS clients directly attached to the same network switch as the MDC systems. Any routing required for metadata traffic will incur additional latency that impacts performance.

It can be useful to use a tool like netperf to help verify the Metadata Network performance characteristics. For example, if netperf -t TCP_RR -H <host> reports less than 4,000 transactions per second capacity, a performance penalty may be incurred. You can also use the netstat tool to identify tcp retransmissions impacting performance. The cvadmin “latency-test” tool is also useful for measuring network latency.

Note the following configuration requirements for the metadata network:

  • In cases where gigabit networking hardware is used and maximum StorNext performance is required, a separate, dedicated switched Ethernet LAN is recommended for the StorNext metadata network. If maximum StorNext performance is not required, shared gigabit networking is acceptable.