Vm.max_map_count recommendations, mongodb 6/7?

Ops and Admin
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2

Hi @Derek_Cox

The full log output suggests the recommended value for the configured system. Check the log or use db.adminCommand({getLog: 'startupWarnings'}).log.forEach(l => printjson(l))

If the Operations Checklist, UNIX ulimit Settings and Production Notes were followed then this value should be 102400.

This is derived from net.maxIncomingConnections * 2

The default net.maxIncomingConnections per the below should be 64000 * 0.8

64000 from the ulimit set(this is usually done in the mongod.service file for RPM and deb installs)

https://www.mongodb.com/docs/manual/reference/configuration-options/#mongodb-setting-net.maxIncomingConnections

net.maxIncomingConnections

Type: integer

Default (Windows): 1,000,000

Default (Linux): (RLIMIT_NOFILE) * 0.8

https://github.com/mongodb/mongo/blob/e1aa498db8bee013a82646b02f04ee878e0e4bbf/src/mongo/db/startup_warnings_mongod.cpp#L286

size_t requiredMapCount = 2 * maxConns;