Is it safe to clear pagecache

Elastic Stack Elasticsearch
1

Hi., to All.
Good Evening.

Generally elasticsearch occupies a lot of pagecache, does it safe to use the command
'echo 3 > /proc/sys/vm/drop_caches'
to clear pagecache? even when data is indexing?

Thanks to you all.

regards

2

This is intended. Elasticsearch performance relies a lot on OS level filesystem cache for indexing but mostly for querying. If that cache is not available then performance will certainly degrade.

3

ok

then
when the memory usage is high ,for example higher than 99%,
is it necessary (or safe?) to clear filesystem cache use the command above?

thanks

4

You should leave as is, do not clear filesystem pagecache. It's cache, so if something else critical to OS health needs memory, OS will release the cache anyway.

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5

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