Why is there a recommendation in Stash Admin panel to use external db for production use ?

[Suresh Nelamangala]

My understanding was that all the repositories are stored in <STASH_HOME>/data/repositories

But in the Administration panel , i find a recommendation to use a external database

I need to know to what extent is the DB going to be used and how large/scalable the DB should be?

Can I use the existing JIRA DB server that I have and co-host the stash DB ?

Are those pull requests , add-on plugin generated data like graphs, code comments etc stored in DB ?

[Jens Schumacher [Atlassian] · Accepted solution]

From the Stash docs:

Why would I want to use an external database?

Stash ships with an embedded database that is great for evaluation purposes, but for production installations we recommend that you make use of one of the supported external databases, for the following reasons:

Improved protection against data loss: The Stash built-in database, which runs HSQLDB, is susceptible to data loss during system crashes. External databases are generally more resistant to data loss during a system crash. HSQLDB is not supported in production environments and should only be used for evaluation purposes.

Performance and scalability: If you have a large number of users on your Stash instance, running the database on the same server as Stash may slow it down. When using the embedded database, the database will always be hosted and run on the same server as Stash, which will limit performance.

Unified back-up: Use your existing DBMS tools to back up your Stash database alongside your organisation's other databases.

More generally:

Although Stash's database usage is currently limited to metadata, pull requests, comments, user/group information and setting... it's likely to expand over time and it's recommended that you use an external database for production.

Whether you can use your existing database really depends on your usage. If your existing database already suffers under the load of JIRA, you might want to look into hosting it on a different server. Otherwise you should be fine.