卡桑德拉的动态告密者

Question

在查看cassandra.yaml文件中以下参数的意义时，请注意我们拥有的各种告密类型。

dynamic_snitch_update_interval_in_ms: 100
dynamic_snitch_reset_interval_in_ms: 600000
dynamic_snitch_badness_threshold: 0.1

在新的Cassandra版本中，这些参数仍然具有有意义的意义吗？

谢谢 布彭

Answer 1

动态小节不是一种小节，而是用于包装您确定的选择小节的包装器。它使snitches能够监视读取延迟，并帮助协调器确定可能要读取的最佳节点。有关here的更多信息，请参见cassandra.yaml file。

对于参数，{{3}}中的每个参数都有简短说明：

# controls how often to perform the more expensive part of host score
# calculation
dynamic_snitch_update_interval_in_ms: 100 

# controls how often to reset all host scores, allowing a bad host to
# possibly recover
dynamic_snitch_reset_interval_in_ms: 600000

# if set greater than zero, this will allow
# 'pinning' of replicas to hosts in order to increase cache capacity.
# The badness threshold will control how much worse the pinned host has to be
# before the dynamic snitch will prefer other replicas over it.  This is
# expressed as a double which represents a percentage.  Thus, a value of
# 0.2 means Cassandra would continue to prefer the static snitch values
# until the pinned host was 20% worse than the fastest.
dynamic_snitch_badness_threshold: 0.1