Is it safe to clear pagecache

[596375269]

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

[thiago (Thiago Souza)]

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.

[596375269]

@thiago

intended

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

[thiago (Thiago Souza)]

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.