Exadata Cell Metrics and Alerts

Exadata Cell metrics get written to disk every hour by default.

what about cell alerts, do cell alerts also get written to disk every hour ?

which process writes the alerts to disk, CELLSRV or MS?

Which process does the accumulation of alerts in memory CELLSRV or MS?

Trying to understand where and how the CELL Alerts get accumulated and how and when are they stored to disk.