[LU-19054] allow limiting the number of clients connected to the filesystem

• Type: Improvement
• Resolution: Unresolved
• Priority: Medium
• Affects Version/s: Lustre 2.16.0
• Labels: easy medium
• Severity: 3
• Assignee: Max Dilger
• Reporter: Andreas Dilger

Description

In some circumstances it would be useful to limit the number of clients that can connect to a server (target). This could be needed as a safeguard to avoid overloading the server in case of limited hardware configurations in a virtual hosting environment, or possibly during system maintenance to prevent all clients from connecting to the servers. Connections from other servers (with OBD_CONNECT_MDS or LWP reverse connections from the OSTs) should not be subject to the connection limit.

It likely makes sense to also allow a matching per-nodemap tunable limit, so that this can be managed on a per-tenant basis.

To avoid accounting problems when there are multiple targets (MDTs or OSTs) on the same server, the client connection (export) counting should be done on a per-target basis, and not per server.

Issue Links

• is related to: LU-17514 hint for expected number of connected clients