Although a single PostERP instance (a single running Linux process) supports an unlimited number of databases, I recommend that you use only one database to support the information system of the entire enterprise group. The reasons follow:

• The performance of PostERP server software is extremely high.
  You run Linux, PostgreSQL, and PostERP server software on an affordable, standard hardware server, and the PostERP server software will respond to thousands of users at lightning speed.
• You adhere to the principle of a single source of truth and avoid the tedious task of synchronizing multiple databases. Realize the ideal of [data sharing] and avoid countless difficult problems such as [data duplication], [data inconsistency], [information backwardness], etc.
• The more significant benefit is that you provide customers with unparalleled service quality.

Assume that your group includes a bank, a life insurance company, and a securities firm.

After customer Mary opens a bank account, her basic information is immediately accessible to the life insurance company and securities firm, eliminating the need for Mary to travel and repeatedly fill out forms, present ID, sign, and stamp. Employees at the life insurance company and securities firm also don't have to repeatedly copy and enter this information.

Mary can immediately use the bank's website to pay life insurance premiums and immediately use the brokerage firm's trading software to trade stocks.

Mary uses one account and password to log into the websites of bank, life insurance company, and securities firm. Without any effort from IT staff, customers automatically receive the supreme service quality of "single sign-on."

Employees at the US branch operate PostERP in English, while employees at the Vietnam branch operate PostERP in Vietnamese.

The IT staff responsible for the bank's ERP system continuously expands the bank's ERP application by operating a single PostgreSQL database. The same is true for the IT teams responsible for life insurance companies and securities firms.

In the process of customizing each company's ERP application, IT personnel do not need to update or restart the PostERP server software, nor do they need to update the PostERP front-end software that runs on the browser.

The entire group's IT staff only needs to maintain and back up one PostgreSQL database, one primary server hardware, and PostERP software. (IT staff can, of course, set up standby servers.)