Redistributing Shards across Index Nodes

Unlike archive nodes, which are sized according to the number of users, Index servers are sized according to the number of documents being processed. Note that a typical Index server with 32GB of RAM is sufficient to process 50 million documents, or approximately 25 million emails without indexing attachments. If you experience slowness in processing, this is likely due to loads placed on the Index server. Contact Support to assist with diagnosing the source of the slowness. Redistributing shards across the index nodes you have deployed could alleviate the problem.

NOTE
It is typical for each Index server to hold 8 “shards”. Each shard holds the indexes for a certain number of users. After adding an Index server, it is recommended to distribute the existing shards evenly across the existing and new Index (i.e. 4 shards on Index 1 and 4 shards on Index 2).