[jira] [Commented] (CASSANDRA-4839) Online toggle for node write-only status

["Jonathan Ellis (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-4839?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13681707#comment-13681707 ] 

Jonathan Ellis commented on CASSANDRA-4839:
-------------------------------------------

Doesn't this approach mean that as soon as a compaction starts your severity will get set to whatever the compaction calculated?  I think you need some kind of flag that says "this is manually set, don't mess with it."
                
> Online toggle for node write-only status
> ----------------------------------------
>
>                 Key: CASSANDRA-4839
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-4839
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>            Reporter: Rick Branson
>            Priority: Minor
>         Attachments: 4839_revised.txt, 4839.txt
>
>
> It would be really great if users could disable/enable reads on a given node, while still allowing write operations to take place. This would be similar to how we enable/disable thrift and gossip using JMX.
> The scenario for using this is that often a node needs to be brought down for maintenance for a few minutes, and while the node is catching up from hints, which can take 10-30 minutes depending on write load, it will serve stale data. Do the math for a rolling restart of a large cluster and you have potential windows of hours or days where a large amount of inconsistency is surfacing.
> Avoiding this large time gap of inconsistency during regular maintenance alleviates concerns about inconsistent data surfaced to users during normal, planned activities. While a read consistency >ONE can indeed be used to prevent any inconsistency from the scenario above, it seems ridiculous to always incur the cost to cover the 0.1% case.
> In addition, it would open up the ability for a node to (optionally) automatically "go dark" for reads while it's receiving hints after joining the cluster or perhaps during repair. These obviously have their own complications and justify separate tickets.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira