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https://issues.apache.org/jira/browse/KUDU-2508?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Alex Rodoni closed KUDU-2508.
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> nscd should be recommended even when /etc/hosts is used for name resolution
> ---------------------------------------------------------------------------
>
> Key: KUDU-2508
> URL: https://issues.apache.org/jira/browse/KUDU-2508
> Project: Kudu
> Issue Type: Bug
> Components: documentation
> Affects Versions: n/a
> Reporter: Adar Dembo
> Assignee: Alex Rodoni
> Priority: Major
> Fix For: 1.9.0
>
>
> It's been observed in several clusters in the wild that on old platforms like
> el6, name resolution can be slow even when /etc/hosts is used. That's because
> opening /etc/hosts requires the creation of an mmap, which means the kernel
> has to take mmap_sem for writing, and that can contend with all sorts of
> other system activity. Furthermore, glibc synchronizes all resolution on a
> single lock, so there's opportunity for contention there. See [this mailing
> list
> post|http://mail-archives.apache.org/mod_mbox/kudu-user/201711.mbox/%3ccady20s4epet5ghnqz7hz13coy-1svunnnoz8dxrn+yxrlx5...@mail.gmail.com%3E]
> for more details.
> We should document that for better scalability on nodes hosting many
> replicas, it's best to use nscd to cache this kind of name resolution too.
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