[SERVER-83775] Do not balance data between shards owning more than the ideal data size Created: 01/Dec/23 Updated: 02/Jan/24 Resolved: 20/Dec/23 |
|
| Status: | Closed |
| Project: | Core Server |
| Component/s: | Sharding |
| Affects Version/s: | 6.0.3, 7.0.0, 7.2.0 |
| Fix Version/s: | 7.2.1, 7.3.0-rc0, 6.0.13, 7.0.6 |
| Type: | Bug | Priority: | Major - P3 |
| Reporter: | Pierlauro Sciarelli | Assignee: | Pierlauro Sciarelli |
| Resolution: | Fixed | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
|
||||||||||||
| Assigned Teams: |
Catalog and Routing
|
||||||||||||
| Backwards Compatibility: | Fully Compatible | ||||||||||||
| Operating System: | ALL | ||||||||||||
| Backport Requested: |
v7.2, v7.0, v6.0
|
||||||||||||
| Sprint: | CAR Team 2023-12-25 | ||||||||||||
| Participants: | |||||||||||||
| Story Points: | 2 | ||||||||||||
| Description |
|
The data size aware balancing introduced in v6.0.3+ versions can potentially schedule migrations between shards that are above the optimal data size threshold. The chunk-based balancing was avoiding that by only scheduling migrations to shards with a sufficiently low number of chunks. ExampleThere are 400GB to spread across 4 shards (ideally 100GB per shard) currently distributed in the following way:
Next balancing round (currently):
Expected next balancing round after fixing this:
(Problem/solution very similar to |
| Comments |
| Comment by Githook User [ 29/Dec/23 ] |
|
Author: {'name': 'Pierlauro Sciarelli', 'email': 'pierlauro.sciarelli@mongodb.com', 'username': 'pierlauro'}Message: |
| Comment by Githook User [ 21/Dec/23 ] |
|
Author: {'name': 'Pierlauro Sciarelli', 'email': 'pierlauro.sciarelli@mongodb.com', 'username': 'pierlauro'}Message: GitOrigin-RevId: a30880ebcb903444463300e967809f257df13d10 |
| Comment by Githook User [ 21/Dec/23 ] |
|
Author: {'name': 'Pierlauro Sciarelli', 'email': 'pierlauro.sciarelli@mongodb.com', 'username': 'pierlauro'}Message: GitOrigin-RevId: 02b922dfc9a930e0e8f432f10d8f4d50c6a34500 |
| Comment by Githook User [ 20/Dec/23 ] |
|
Author: {'name': 'Pierlauro Sciarelli', 'email': 'pierlauro.sciarelli@mongodb.com', 'username': 'pierlauro'}Message: GitOrigin-RevId: d68e62491c9eab5300b498a304f6601fd4dca79f |