cassandra-pr mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From jolynch <...@git.apache.org>
Subject [GitHub] cassandra pull request #212: Rework the wait for healthy logic to count down...
Date Wed, 07 Nov 2018 23:00:23 GMT
Github user jolynch commented on a diff in the pull request:

    https://github.com/apache/cassandra/pull/212#discussion_r231711085
  
    --- Diff: src/java/org/apache/cassandra/config/Config.java ---
    @@ -376,9 +376,31 @@
     
         public String full_query_log_dir = null;
     
    -    // parameters to adjust how much to delay startup until a certain amount of the cluster
is connect to and marked alive
    -    public int block_for_peers_percentage = 70;
    +    /**
    +     * When a node first starts up it intially thinks all other peers are DOWN, and then
as the initial gossip
    +     * broadcast messages comes back nodes transition to UP. These options configure
how many nodes can remain in
    +     * DOWN state before we make this node available as a coordinator, as well as an
overall timeout on this process
    +     * to ensure that startup is not delayed too much.
    +     *
    +     * The defaults are tuned for LOCAL_ONE consistency levels with RF=3, and have natural
settings for other CLs:
    +     *
    +     *     Consistency Level | local_dc     | all_dcs
    +     *     --------------------------------------------------------
    +     *     LOCAL_ONE         | default (2)  | default (any)
    +     *     LOCAL_QUORUM      | 1            | default (any)
    +     *     ONE               | any          | RF - 1
    +     *     QUORUM            | any          | (RF / 2) - 1
    +     *     ALL               | default      | 0
    +     *
    +     * A concrete example with QUORUM would be if you have 3 replicas in 2 datacenters,
then you would set
    +     * block_for_peers_all_dcs to (6 / 2) - 1 = 2 because that guarantees that at most
2 hosts in all datacenters
    +     * are down when you start taking client traffic, which should satistfy QUORUM for
all RF=6 QUORUM queries.
    +     */
    +    public int block_for_peers_local_dc = 2;
    --- End diff --
    
    We ended up going the direction of a boolean.


---

---------------------------------------------------------------------
To unsubscribe, e-mail: pr-unsubscribe@cassandra.apache.org
For additional commands, e-mail: pr-help@cassandra.apache.org


Mime
View raw message