We using SQL Litespeed and doing daily diff backups and once a week full backups. I see weird entry in event viewer only when full backups occur and I dont see when SQL diff backups are running. The event viewer has following 3 messages in row for every database.
Source:SQL Server Instance Name
category:2
Event ID:3197
user:NT Authority
Description:I/O is frozen on database SMS_ . No user action is required. However, if I/O is not resumed promptly, you could cancel backup.
and the very next event viewr is
Source:SQL Server Instance Name
category:2
Event ID:3198
user:NT Authority
Description:I/O was resumed on database SMS_ . No user action is required.
and the next one says database was backed up successfully.