Enabling Jumbo Frame for the storage network is one of the most effective ways to improve throughput. It is also the easiest configuration item to configure half and half. Large packets will be directly discarded on misaligned devices. This article explains how to open it in three steps: scenario, alignment, and verification.

First confirm whether the scene is beneficial

Jumbo increases the MTU from 1500 to about 9000, diluting the header and interrupt overhead of each byte of data, and has obvious effects on large continuous transmission of iSCSI, NFS, backup and virtual machine migration; small IO-intensive businesses and ordinary office networks have limited benefits. It is not recommended to open the cross-city high-latency or multi-hop links at the first time. The local storage network must be stable first.

End-to-end alignment is a prerequisite

The source network card, each switch in the middle, and the destination network card must all set MTU 9000 simultaneously. If a device is leaked, large packets will be black holes but small packets will be normal. The fault performance is inconsistent and extremely difficult to locate. In Windows, set Jumbo Frame in the advanced properties of the network card. In Linux, use ip link set mtu 9000 and write the persistent configuration. The switch checks the system MTU and port configuration. pressData center high-speed interconnection solutionA common practice is to separate the storage network and the business network in grayscale, and only move one network segment at a time.

Verification is done in two steps

  • For Windows, use ping -f -l 8972, for Linux, use ping -M do -s 8972. Only when large packets are not lost can the path be fully accessible.
  • Then use iperf3 or real storage read and write to compare the throughput and CPU usage before and after it is turned on.
  • Applications that use UDP must confirm that the business layer packet size is synchronously converged, otherwise the excess part will be discarded directly.

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