Replace pids_limit with memory limits #181
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Add mem_limit settings with documentation links to help users configure appropriate memory limits based on their deployment size. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
hanzei
changed the title
| restart: ${RESTART_POLICY} | ||
| security_opt: | ||
| - no-new-privileges:true | ||
| pids_limit: 100 |
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Can we document in this PR why pids_limit is not appropriate for Postgres + our default max connections? (Just so we can trace the history here.)
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Where would we document that? In the general docs at https://docs.mattermost.com/deployment-guide/server/deploy-containers.html?
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I think even a description in this pull request that explains the context would suffice as a "paper trail" for why we're making the change. That being said, given our new understanding of the impact of this setting, it might even be worth an FAQ in the container docs linked above.
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Good point 👍 I've updated the PR description and submitted mattermost/docs#8695
Summary
Replace
pids_limitwithmem_limitfor postgres and mattermost services to prevent connection failures under normal load.Problem
A customer reported PostgreSQL connection failures caused by hitting the
pids_limit: 100constraint. PostgreSQL creates one process per database connection, meaning the database could only handle ~90-95 concurrent connections before exhausting the PID limit. This is too restrictive for production deployments with moderate traffic.Changes
pids_limit: 100, addedmem_limit: 16Gpids_limit: 200, addedmem_limit: 4GRationale
Memory limits provide better resource protection while allowing PostgreSQL to scale connections naturally based on actual load. The
pids_limitapproach was overly restrictive and caused operational issues in real-world scenarios.The default values chosen (16G/4G) are based on typical medium-sized deployment requirements and can be adjusted per the scaling documentation.
Documentation
Inline comments added referencing https://docs.mattermost.com/administration-guide/scale/scaling-for-enterprise.html