[LU-9121] Multi-Rail: User Defined Selection Policy

• Type: New Feature
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.15.0
• Assignee: Amir Shehata (Inactive)
• Reporter: Amir Shehata (Inactive)

Description

It is sometimes desirable to fine tune the selection of local/remote NIs used for communication. For example currently if there are two networks an o2ib and a tcp network, both will be used. Especially if the traffic volume is low the credits criteria will be equivalent between the nodes, and both networks will be used in round robin. However, the user might want to use one network for all traffic and keep the other network free unless the other network goes down.

User Defined Selection Policies (UDSP) will allow this type of control. 

UDSPs are configured from lnetctl via either command line or YAML config files and then passed to the kernel. Policies are applied to all local networks and remote peers then stored in the kernel. Whenever new peers/peer_nis/local networks/local nis are added they are matched against the rules.

Issue Links

• has to be finished together with: LUDOC-438 LNet UDSP Documentation