[DOCS-15792] [Server] Migration thresholds are missing from Sharded Cluster Balancer topic Created: 19/Dec/22  Updated: 30/Oct/23  Due: 19/Apr/23  Resolved: 19/Apr/23

Status: Closed
Project: Documentation
Component/s: Server
Affects Version/s: 6.0.0
Fix Version/s: Server_Docs_20231030

Type: Task Priority: Critical - P2
Reporter: Dmitry Ryabtsev Assignee: Joseph Dougherty
Resolution: Fixed Votes: 1
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Participants:
Days since reply: 43 weeks, 1 day ago
Epic Link: DOCSP-22649

 Description   

Currently balancing threshold are not clarified and the section contains a link to itself:

https://www.mongodb.com/docs/manual/core/sharding-balancer-administration/#std-label-sharding-migration-thresholds

Also, the "migration thresholds" link points to the same section - that should be fixed/removed.

Explanation provided by engineering
The migration threshold for 6.0 is 3x the configured chunk size for a given collection. So for the default chunk size (for 6.0) of 128MB, two shards must have a data size difference for a given collection of at least 384MB for a migration to occur.

At steady state it's ok to have shards' data sizes slightly differing. Much better than continuously moving data to reach perfect equality.



 Comments   
Comment by Ashley Brown [ 11/Apr/23 ]

Bumping priority due to linked Support ticket.

Generated at Thu Feb 08 08:13:53 UTC 2024 using Jira 9.7.1#970001-sha1:2222b88b221c4928ef0de3161136cc90c8356a66.