[DOCS-10032] Clarify the semantics of replica set tags Created: 24/Mar/17 Updated: 23/Aug/17 Resolved: 12/Apr/17 |
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| Status: | Closed |
| Project: | Documentation |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Improvement | Priority: | Major - P3 |
| Reporter: | Kevin Adistambha | Assignee: | Kevin Adistambha |
| Resolution: | Done | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
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| Days since reply: | 6 years, 44 weeks, 1 day ago | ||||||||
| Description |
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The docs page in https://docs.mongodb.com/manual/tutorial/configure-replica-set-tag-sets/ contains an extensive tutorial & examples regarding the use of replica set tag sets. However, the semantics of the tags themselves are not clearly explained. The tags look like a free-form document, where the "key" is the "tag", and the "value" could be anything the user wants. However, this is not true. Both the key and the value of the tags are important. At least with regards to write concern. For example, these tags:
This replica set configuration would imply that writes using a writeConcern setting of either w:"production" or w:"ssd" would propagate the writes to both nodes before returning. Inserting using w:"production", where the members have different values in the tags (i.e. "production": "1" and "production": "2"):
Inserting using w:"ssd", where the members have identical values in the tags (i.e. both members have "ssd": "installed"):
This replica set tag semantics are counter-intuitive, and could be better explained in the docs. Some suggestions:
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| Comments |
| Comment by Githook User [ 12/Apr/17 ] |
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Author: {u'username': u'kevinadi', u'name': u'Kevin Adistambha', u'email': u'kevinadi@gmail.com'}Message: Signed-off-by: kay <kay.kim@10gen.com> |