Veeam or other backup tools may be stomping on SQL Server Backups. The example below is written for Veeam, hower similar things apply to other backup and VM Snapshot tools.
What is Veeam
Veeam is a really incredible tool for backing up virtual machines. It is commonly used in VMWare environments, and some in HyperV environments. It allows for some really great snapshot backup and restore capability. The problem is that by default it doesn’t play well with SQL Server backups.
What does this mean
If Veeam is installed for backing up the entire VM that is running SQL Server, there is an option for Veeam to backup the SQL Server database, and to “Process transaction Logs”, or “Peform copy only. The settings dialog looks something like this depending on the version of Veeam you are using.
If you choose to process transaction logs with the job, Veeam takes a transaction log backup with the full snapshot backup, and stores that transaction log backup, somewhere in the Veeam backup system. If you are the Veeam backup admin and know where to find that backup, and to use it in a log restore situation, then you might get away with that setting. If you don’t know where to get that transaction log file, what Veeam has done is just made it impossible for you to restore your normal transaction logs backups past the time the Veeam backup occurred. If you are using Veeam to manage ALL of your SQL Server backups, then this would be okay, however if you are also using the standard SQL Server backups this breaks the restore chain, and prevents you from restoring any of your normal transaction log backups past the time the Veeam backup occurred.
Instead you should use the Perform a copy only (lets other application use logs) option this allows your normal SQL Server transaction log backups to run just fine, and more importantly allows them to restore just fine.
Even though Veeam is recommending the bad option, it is not the right option if you use normal SQL Server transaction log backups.