SQL differential backup runs as full due to backup start time mismatch
This article applies to:
- Product edition: Phoenix
The SQL differential backup runs as full due to a backup start time mismatch error. The Phoenix agent scans all the databases selected for backup in the backup set, even if one of those has been backed up by a third party or native backup software. Note that while the scan is a full scan, the upload will still be differential.
In each differential backup, Phoenix matches the current (system) database backup start time v/s the saved database backup start time (Phoenix metadata, saved with last full backup). If there is a mismatch, Phoenix converts it to full.
This mismatch occurs in one of the following cases:
- There is a third-party backup or MS-SQL native backup (non-Phoenix backup) running on the Server .
- The database was deleted and a new database was created with the same name on the instance.
Where instance name : ABCNODE-02:
DB name : PAF
Log location: C:\ProgramData\Phoenix\SQL\log\backup\<backupsetID>
You can also download and extract the logs.
[2019-03-19 01:00:44,970] [INFO] [Tid:<_MainThread(MainThread, started 10196)>] Backup start time mismatch for [ABCNODE-02:PAF] found
[2019-03-19 01:00:44,970] [INFO] [Tid:<_MainThread(MainThread, started 10196)>] Backup start time mismatch found, converting to full
Perform any one of the following tasks:
- Disable any third-party backups running on the MS-SQL DB, including SQL native backups.
- Create another backup set for the same SQL server for this specific database.
Note: To create a new backup set, you must uncheck the DB from the current backup set.
- Perform "Copy-only" native backups from the SQL server if disabling backups through third-party or native backups is not possible.