Full, differential and log backups are easy to define and easy to get wrong at 2 AM. This animated guide shows which ones to restore, and in what order.
SQL SERVER – Transaction Logs: The Good, The Bad, and The Ugly
Providing a comprehensive understanding of their role and potential issues. Let us learn about Transaction Logs: The Good, The Bad, and The Ugly.
VLF Growth Rules: How Many Virtual Log Files One Growth Adds
The VLF growth rules say how many virtual log files one log growth adds: one up to 64 MB, eight up to 1 GB, sixteen above. This post measures them on a demo database, shows a log with 68 VLFs from 1 MB steps, and repairs it by shrinking and growing once.
Log File Growth and Instant File Initialization: The 64 MB Rule
The 64 MB rule says log file growth can skip zeroing when instant file initialization is on, but only up to 64 MB. Two trace flags make the SQL Server error log show a 64 MB growth skipping the zeroing and a 65 MB growth zeroing in full. The last section says what to change.
Log File Not Shrinking: Read log_reuse_wait_desc First
A log file not shrinking is explained by one column: log_reuse_wait_desc. A demo database reads LOG_BACKUP and ACTIVE_TRANSACTION from it and shows why the first shrink after a log backup can still fail. A table lists the other reasons with the action for each.
Free Space in Database Files: Check Data and Log Files
To see the free space in database files, compare each file’s size with the pages it uses. This post gives one query for data and log files, adds the free space on the drive, and checks the log figure against a second source.
Recovery Model Changes and the Log Backup Chain
Explain the log backup chain across FULL and SIMPLE changes, inspect recovery LSNs and backup history, and establish a new backup boundary.