Stack Overflow how stores data in Redis and ElasticSearch? Which category of data?

If i have a class , For Example :

class Post
{

 public string Id{ get; set; }

 public string Body{ get; set; }

 public bool Deleted{ get; set; }

 public DateTime CreateDateTime{ get; set; }

}

I store that object in Redis for caching my data

_redis.Get<Post>(Id);

and store that object in ElasticSearch for search query

_elasticSearch.Get<Post>(post=>post.Body.Content("text") && post.Deleted!=False); // Example not real

is it true!? duplicate data? What is the best way for store this object for search and for cache? which structure ?Which classified data better for store data in ElasticSearch and Redis ?