BUG #16314: Database Cache Hit Ratio (Warning)

The following bug has been logged on the website:

Bug reference:      16314
Logged by:          Rajiv Ranjan
Email address:      rajiv.mca08@gmail.com
PostgreSQL version: 9.6.0
Operating system:   Red Hat Enterprise Linux Server release 7.6 (Maip)
Description:

Hi,

Currently, we are receiving a warning "Database Cache Hit Ratio
(%)(Warning)" from one of the monitoring tools.

We use Postgres database for Jira, confluence, and bitbucket application and
hosted on a different machine and only 35% disc space is used.

Database warning “Database Cache Hit Ratio” issue has been fixed by
increasing the below values however after a few days of stability the
warning is back hence not sure increasing the below parameters are correct
or not.

shared_buffers = 2GB
effective_cache_size = 6GB
maintenance_work_mem = 512MB

Could you please suggest how much we can increase the parameters and how
does it impact the database. 

Thanks,
Rajiv Ranjan