[SERVER-37233] Increase in disk i/o for writes to replica set Created: 20/Sep/18 Updated: 27/Oct/23 Resolved: 24/Dec/18 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | Storage |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Bug | Priority: | Major - P3 |
| Reporter: | Bruce Lucas (Inactive) | Assignee: | Kelsey Schubert |
| Resolution: | Works as Designed | Votes: | 1 |
| Labels: | dmd-perf | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Attachments: |
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| Operating System: | ALL | ||||||||||||||||||||
| Sprint: | Storage NYC 2018-10-08, Storage NYC 2018-10-22, Storage NYC 2018-11-05 | ||||||||||||||||||||
| Participants: | |||||||||||||||||||||
| Case: | (copied to CRM) | ||||||||||||||||||||
| Description |
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Issue Summary as of Dec 23, 2018 ISSUE SUMMARY ISSUE IMPACT To ensure writes received by secondaries are durable on the primary, oplog entries are journaled and written to disk before being replicated. As a result, it is beneficial for mongod to flush the journal more rapidly, and consequently more heavily utilize the disk, to make these oplog entries available for replication as soon as possible. If the disk is fully utilized, the frequency of journal flushes will decrease to provide the same overall throughput of the node as compared to the performance of disk-bound workloads in earlier versions of MongoDB. AFFECTED VERSIONS Original descriptionThis is a continuation of Simple insert workload:
Results on 3.4.17, 3.6.5, and 3.6.6 respectively:
Note that while This becomes clearer if we simulate an application that is doing a low rate of inserts:
Results on 3.4.17, 3.6.5, and 3.6.6 respectively:
For this workload |