Missing replica shards

hi community
i'm a beginner in ELK, so i can't resolve this problem.
the Elasticsearch overview show me that are Missing replica shards, also the health is yellow. Also, i uploaded a file to kibana, but it can't visualize it.
thanks for help

Welcome to our community! :smiley:

That's more of a recommendation/best practise. As if you don't have replica shards and you lose your node, you can lose your data.