Todd Lipcon created KUDU-1447:
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Summary: Document recommendation to disable THP
Key: KUDU-1447
URL: https://issues.apache.org/jira/browse/KUDU-1447
Project: Kudu
Issue Type: Improvement
Components: documentation
Affects Versions: 0.8.0
Reporter: Todd Lipcon
Assignee: Todd Lipcon
Doing a bunch of cluster testing, I finally got to the root of why sometimes
threads take several seconds to start up, causing various timeout issues, false
elections, etc. It turns out that khugepaged does synchronous page compaction
while holding a process's mmap semaphore, and when that's concurrent with lots
of IO, can block for several seconds.
https://lkml.org/lkml/2011/7/26/103
To avoid this, we should tell users to set hugepages to "madvise" or "never" --
it's not sufficient to just disable defrag, because khugepaged still runs in
the background in that case and causes this sporadic issue.
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