Elasticsearch is an open-source search engine that carries out an index search instead of searching for text directly, resulting in faster search results. Elasticsearch is better at managing a large number of indexes and can handle complex index searches much faster than a SQL database.
In short, Elasticsearch is much more scalable and performs faster in comparison to SQL databases.
This is applicable only to the existing O365 Manager Plus customers using build 4323 or older, or customers that have recently updated to the latest build. Elasticsearch will be the default search engine for those who started using the product after build 4323.
When you log in to the product, a Data Engine Update pop-up will appear to notify you that the product has adopted Elasticsearch to enhance performance. This pop-up will show the size of the data to be migrated and the approximate time taken for the migration to complete. You can either choose to migrate immediately or schedule the migration for later.
To migrate immediately:
Choose Migrate now from the pop-up to begin immediate migration. During the migration, only some data is available for auditing, alerting, and content search. You will have to wait until the migration is complete to query all your data.
To conduct a scheduled migration: