Elasticsearch become slow

Hello Team,

I am having elasticsearch cluster with 7 nodes and 10 indexes. Each node is having following configuration ...

Node Config Info
-500GB Storage

Custer configuration
=1 - Front end + master node
=1 - Front end
=5 - Data node.

Index Info
Index1 - 9 are small, they are having max 3000 documents each. 5 shards and 1 replica.
Index10 - is very big its having 80 million documents. 10 shards and 1 replica. It has having three types url,type1 and type2. Type 2 is child type of url. Everyday I am updating child records and they need to be update.


-Search is slow.
-Parent - child search is slow.
-Indexing child records also slow.
-After restart cluster taking time to recover.

Thanks in advance, please share your thoughts on this.