[jira] [Commented] (CASSANDRA-3569) Failure detector downs should not break streams

["Joshua McKenzie (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-3569?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13987023#comment-13987023 ] 

Joshua McKenzie commented on CASSANDRA-3569:
--------------------------------------------

nio isn't interested in us getting the integer file descriptor for the underlying sockets without cracking open some internals and using reflection to rip out private member variables.  I don't think this is the right way to go - it'll be messy (reflecting out 2 private members from SocketAdapter down), java platform-dependent, and brittle.

As for using sysctl or modifying the registry (Windows) on cassandra start - that isn't the least surprising thing we could do as there would be side effects to other processes running on these machines.  Do we have a precedent at this time for changing global system configuration settings on startup of the daemon or during rpm install?

Maybe adding an optional parameter in the yaml for tcp_keepalive_interval and selectively setting that if the users opt-in.  Still seems like it doesn't address our need of a default-state with improved behavior though.



> Failure detector downs should not break streams
> -----------------------------------------------
>
>                 Key: CASSANDRA-3569
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-3569
>             Project: Cassandra
>          Issue Type: New Feature
>            Reporter: Peter Schuller
>            Assignee: Joshua McKenzie
>             Fix For: 2.1 rc1
>
>         Attachments: 3569-2.0.txt
>
>
> CASSANDRA-2433 introduced this behavior just to get repairs to don't sit there waiting forever. In my opinion the correct fix to that problem is to use TCP keep alive. Unfortunately the TCP keep alive period is insanely high by default on a modern Linux, so just doing that is not entirely good either.
> But using the failure detector seems non-sensicle to me. We have a communication method which is the TCP transport, that we know is used for long-running processes that you don't want to incorrectly be killed for no good reason, and we are using a failure detector tuned to detecting when not to send real-time sensitive request to nodes in order to actively kill a working connection.
> So, rather than add complexity with protocol based ping/pongs and such, I propose that we simply just use TCP keep alive for streaming connections and instruct operators of production clusters to tweak net.ipv4.tcp_keepalive_{probes,intvl} as appropriate (or whatever equivalent on their OS).
> I can submit the patch. Awaiting opinions.



--
This message was sent by Atlassian JIRA
(v6.2#6252)