Eventually, we should document where you can modify where files are stored, and where they're stored by default:

MONITORING AGENT
configure in UI > Administration > Agents > Monitoring Agent Log Settings

• Default Path: /var/log/mongodb-mms-automation/monitoring-agent.log

BACKUP AGENT
configure in UI > Administration > Agents > Backup Agent Log Settings

• Default Path: /var/log/mongodb-mms-automation/backup-agent.log

AUTOMATION AGENT
configure in UI > Administration > Agents > MongoDB & Agents Binary Download Directory (Linux):

• Default Path: /var/lib/mongodb-mms-automation
• NOTE the keyfile is also stored in this same location / setting (e.g. by default /var/lib/mongodb-mms-automation/keyfile) when authentication is enabled

configure in /etc/mongodb-mms/automation-agent.config:

• Default logFile=/var/log/mongodb-mms-automation/automation-agent.log
• Default mmsConfigBackup=/var/lib/mongodb-mms-automation/mms-cluster-config-backup.json

MANAGED MONGODB DEPLOYMENT
configure in Deployment > Process > Edit:

• Default DB Path: /data
• Default Log File Path: /data/mongodb.log

OPS MANAGER APP
configure in /opt/mongodb/mms/conf/conf-mms.properties:
If Local automation.versions.source=local

• Default automation.versions.directory=/opt/mongodb/mms/mongodb-releases/

Related, the default Ops Manager application logs path:
/opt/mongodb/mms/logs

BACKUP DAEMON
configure in /opt/mongodb/mms-backup-daemon/conf/conf-daemon.properties

• Default rootDirectory=/var/lib/mongodb/backup/
• Default mongodb.release.directory=/opt/mongodb/mms-backup-daemon/mongodb-releases/

Related, the default Backup Daemon logs path:
/opt/mongodb/mms-backup-daemon/logs