How to verify if PMTUD is enabled in a PowerScale cluster or not
Summary: PMTUD stands for Path MTU Discovery. It is a technique used in computer networking to determine the maximum transmission unit (MTU) size on the network path between two hosts, usually across the Internet. The MTU is the largest size of a data packet that can be transmitted over a network. PMTUD works by allowing two communicating hosts to dynamically discover the largest packet size they can exchange without fragmentation. This is crucial for efficient data transmission, as it helps prevent packet fragmentation, which can degrade network performance. ...
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Instructions
In the latest onefs version, PMTUD is enabled by default.
To verify if its enabled or not in the PowerScale cluster Please run below command.
Lab-1# sysctl net.inet.tcp.path_mtu_discovery. net.inet.tcp.path_mtu_discovery: 1
If it is not enabled, we can enable it using:
Lab-1# isi_sysctl_cluster net.inet.tcp.path_mtu_discovery=1
If in case looking to disable the value can be set to 0 as below:
Lab-1# isi_sysctl_cluster net.inet.tcp.path_mtu_discovery=0
Affected Products
PowerScale, Isilon, PowerScale OneFSArticle Properties
Article Number: 000224097
Article Type: How To
Last Modified: 07 Jul 2025
Version: 4
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