Add a section that explains the downtime with replica 1 #163
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| | minAvailableReplicas | 1 | <p>Applicable for rebalance with downtime=false.</p><p>This is the <strong>minimum number of replicas that are expected to stay alive</strong> through the rebalance.</p> | | ||
| | bestEfforts | false | <p>Applicable for rebalance with downtime=false.</p><p>If a no-downtime rebalance cannot be performed successfully, this flag <strong>controls whether to fail the rebalance or do a best-effort rebalance</strong>.</p> | | ||
| | reassignInstances | false | Applicable to tables where the instance assignment has been persisted to zookeeper. Setting this to true will make the rebalance **first update the instance assignment, and then rebalance the segments**. | | ||
| | bootstrap | false | Rebalances all segments again, **as if adding segments to an empty table**. If this is false, then the rebalance will try to minimize segment movements. | | ||
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| ### Rebalance with only 1 replica | ||
| In general, when the table config uses only 1 replica, the downtime may be affected. |
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Just a minor reword if it makes sense.
"The downtime option is not relevant when rebalance is initiated on a table with a replication factor of 1 and there's no further change to the replication factor. In this case, there'll be a downtime during rebalance.
However when the rebalance is initiated for increasing replication (from 1 to > 1), the downtime flag can be used (set to false) to avoid downtime."
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i think with downtime = false and replication = 1 (with no changes to final replication count), the rebalance will itself be blocked. So this would be untrue "In this case, there'll be a downtime during rebalance"
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What do you mean with the rebalance itself will be blocked?
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I've recently found this PR is still open. I'm going to apply the change suggested by Manish. About the suggestion from Neha... do we know the actual behavior? IIRC I didn't actually tested that and the written here is what I inferred seen the code, but I may be wrong.
The description that explains the case when replica is 1 wasn't very clear. Specifically, when increasing the number of replicas.
This PR adds a couple of paragraphs to specifically focus on the replica 1 case.