Sql-server – Breaking transaction log chain with backups

Frankly, there's no reason NOT to run Transaction Log backups at a much more frequent rate. A transaction log backup doesn't HURT anything. (In MOST scenarios it's just going to take a bit of CPU and disk activity - but it's typically almost negligible.)

Moreover, you can both increase your coverage AND boost performance by moving log-file backups to less performant disk: SQL Server Magazing: Maximize Storage Performance

By increasing frequency of your backups, you'll decrease your window of potentially lost data. (Technically, if SQL Server crashes you can sometimes recover lost transactions since the last FULL/DIFFERNTIAL backup IF your log file is still intact. But usually, if something has gone wrong enough for you to be backing up in the first place, there's a DECENT chance your log file is gone/toast.)

Feel free to check out the following videos for a bit more background and information on what's going on in terms of backups, logs, and best practices:

SQL Server Backups Demystified

SQL Server Logging Essentials

Managing SQL Server 2005/2008 Log Files

SQL Server Backup Best Practices

Some interesting suggestions here, which all seem to show misunderstanding about how log backups work. A log backup contains ALL transaction log generated since the previous log backup, regardless of what full or differential backups are taken in the interim. Stopping log backups or moving to daily full backups will have no effect on the log backup sizes. The only thing that affects the transaction log is a log backup, once the log backup chain has started.

The only exception to this rule is if the log backup chain has been broken (e.g. by going to the SIMPLE recovery model, reverting from a database snapshot, truncating the log using BACKUP LOG WITH NO_LOG/TRUNCATE_ONLY), in which case the first log backup will contain all the transaction log since the last full backup - which restarts the log backup chain; or if the log backup chain hasn't been started - when you switch into FULL for the first time, you operate in a kind of pseudo-SIMPLE recovery model until the first full backup is taken.

To answer your original question, without going into the SIMPLE recovery model, you're going to have to suck up backing up all the transaction log. Depending on the actions you're taking, you could take more frequent log backups to reduce their size, or do more targeted database.

If you can post some info about the maintenance ops you're doing, I can help you optimize them. Are you, by any chance, doing index rebuilds followed by a shrink database to reclaim the space used by the index rebuilds?

If you have no other activity in the database while the maintenance is occuring, you could do the following:

• make sure user activity is stopped
• take a final log backup (this allows you to recover right up to the point of maintenance starting)
  • switch to the SIMPLE recovery model
  • perform maintenance - the log will truncate on each checkpoint
  • switch to the FULL recovery model and take a full backup
  • continue as normal

Hope this helps - looking forward to more info.

Thanks

[Edit: after all the discussion about whether a full backup can alter the size of a subsequent log backup (it can't) I put together a comprehensive blog post with background material and a script that proves it. Check it out at https://www.sqlskills.com/blogs/paul/misconceptions-around-the-log-and-log-backups-how-to-convince-yourself/]