How many licensees i need , if I have 1 production and 1 back up site which use replicated Database/ index / attachment and NOT online at the same time?

[Tiraphol Pengvanich]

Can i have 1 license , because it's the same information in database

[Nic Brough -Adaptavist-]

One. 

Your production licence entitles you to a "developer" licence, which is explicitly for licencing dev, test and failover machines, so you should be using that, especially for any DR testing.

Atlassian understand the "fun" that can be had with Disaster Recovery, and although you might find the licence agreement has legal complexities, the principle is not quite "same data", but "you have one licence for each production server".  A DR server is your  production when it's active, because the main one has failed.