[SERVER-37541] MongoDB Not Returning Free Space to OS Created: 10/Oct/18 Updated: 07/Jun/23 Resolved: 12/Oct/18 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | Performance, WiredTiger |
| Affects Version/s: | 3.2.11 |
| Fix Version/s: | None |
| Type: | Bug | Priority: | Major - P3 |
| Reporter: | Rakhi Maheshwari | Assignee: | Bruce Lucas (Inactive) |
| Resolution: | Duplicate | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Attachments: |
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| Operating System: | ALL | ||||||||||||
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| Description |
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MongogetCmdLineOpts.txt |
| Comments |
| Comment by Bruce Lucas (Inactive) [ 12/Oct/18 ] | ||||||
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Hi Rakhi, Thanks for your report and for the serverStatus data. We had asked for the diagnostic.data data because it contains a timeseries of serverStatus over an extended period of time and would give us a clearer picture of the extent and history of the issue than the single point-in-time snapshot of serverStatus. From that snapshot we have the following information:
There are two issues here:
Finally, you may be able to get some relief by setting the environment variable TCMALLOC_AGGRESSIVE_DECOMMIT or equivalently the server parameter tcmallocAggressiveMemoryDecommit, which will cause memory to be returned to the o/s more aggressively. We have not enabled this by default as we have observed it to impact performance in some workloads. Since I believe that the issues you are seeing are already covered by other SERVER tickets I'll close this ticket as a duplicate; please watch those tickets for updates, and thanks again for reporting this. | ||||||
| Comment by Rakhi Maheshwari [ 11/Oct/18 ] | ||||||
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Nick Brewer Already attached the files showing diagnostic data with the output of serverStatus,hostInfo buildInfo etc commands. This scenerio of memory utilization is seen repeatedly as it goes down form 40% to 29% and even more less. Please find the attached logs in that scenerio.mongoDebug_10T08102018.log | ||||||
| Comment by Nick Brewer [ 10/Oct/18 ] | ||||||
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rmaheshwari MongoDB uses the operating system's memory management. If you can upload a mongod log and an archive of the dbpath/diagnostic.data directory from an affected node, we can take a closer look at the resource utilization you're seeing. -Nick |