Last night my weekly backup on SQL Server 2014, running on Windows Server 2012 R2, failed with the following error in the log:
failed with the following error: "A nonrecoverable I/O error occurred on file "D:\MSSQL\MSSQL12.MSSQLSERVER\Backup\backup-xxxx.bak:" 112(There is not enough space on the disk.).
When I checked disk space I found there was still 1 GB free, and the .bak file looked ok, all 4GB of it, not compressed.
So I ran a RESTORE VERIFYONLY command on that file:
RESTORE VERIFYONLY FROM DISK = 'D:\MSSQL\MSSQL12.MSSQLSERVER\Backup\backup_xxxx.bak'
The backup set on file 1 is valid.
So which version of the story should I trust?
Note: According to Pinal Dave (http://blog.sqlauthority.com/2016/04/14/sql-server-backup-randomly-failing-error-112-not-enough-space-disk/) the first error is not accurate, especially if using compressed backups.