Situation

Unifi Controller Not Work, Saw Error Log Like :

[2020-12-19T01:41:59,535] <db-server> WARN  db     - Mongo start up failed with rc=134

How

Maybe You Upgrade Unifi Controller Version, Power Went Off Suddenly etc…

Solutions

Step 1

Login To Server, Repair MongoDB.

mongod --dbpath /unifi/data/db --port 27117 --repair

Step 2

Change MongoDB Folder Owner.

chown -R unifi . /unifi/data/db

Step 3

Restart Unifi Controller

docker-compose restart
#or 
docker-compose down
docker-compose up -d

Ref

sysadmin-blog