Feedback: Production Checklist #20518
Description
Page: https://cockroachlabs.com/docs/v25.3/recommended-production-settings.html#cache-and-sql-memory-size
What is the reason for your feedback?
[ ] Missing the information I need
[X] Too complicated
[ ] Out of date
[ ] Something is broken
[ ] Other
Additional details
This section is quite confusing.
On the one hand it suggests that you can set both --cache and --max-sql-memory to 35% of physical memory -
cockroach start --cache=.35 --max-sql-memory=.35 {other start flags}
Then the following formula is given:
(2 * --max-sql-memory) + --cache <= 80% of system RAM
If I decide to set both to 35% and then plug the values into the formula I get
(2 * 35%) + 35% <= 80% of system RAM
105% <= 80% of system RAM
This means that the example cockroach start command is invalid.
Also the following log messages are sent to the main log file in the event of a misconfiguration (this is with v24.3):
W250821 22:36:37.660126 1 1@cli/start.go:1371 ⋮ [T1,n?] 3 the sum of --max-sql-memory (‹31 GiB›), --cache (‹62 GiB›), and --max-tsdb-memory (‹1.2 GiB›) is larger than 75% of total RAM (93 GiB).
This server is running at increased risk of memory-related failures.
Can the docs page be made consistent with the product?
Can we mention to look for this error message somewhere in the docs?
Jira issue: DOC-15028