Differential backup without full backup

  • I don't remember when was last time we had a full backup. We turned off the full backup after we decided to use a third party backup program. I found out this morning that the differential back up has been running daily. The differential back up file size is 100 gb. Is this because the differential one does backup all the changes ever since the last full backup?

  • Probably.

    Yes, differential is all changes since the last full backup.

    But most third party backup software does backups that count as "full" backups. Some don't (doing file-level backups instead), but most of those also don't work very well with SQL Server databases.

    Have you tried restoring from the third-party backups?

    Have you checked the backup tables in msdb to see what the first and last lsn values are for the diff backups? That'll tell you more about what timespan it's covering.

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  • I believe the third party back up is a windows level daily back up. it looks like the diff one doesn't cooperate with the third party one. We never had a chance to retore the third party backup. Since the diff backup failed (due to not enough disk space), I couldn't retrieve the lsn info. I'm a newbie. It could be a silly question. Shouldn't there be a cooperation working between the third party backup and the diff backup. To me, there's no conversation between the two.

  • If the third party backup software isn't updating the backup tables in msdb (system database), then you need to test restoring from those backups. Windows file-level backups generally don't work for restoring databases, because the log file backup and data file backup aren't guaranteed to be synchronized correctly. Have you tested restoring from those backups? (Ignore the diff backup for now. Make sure you can restore from the third-party backups, if you haven't already.)

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  • Remember, the only point of taking a backup is so you can do a restore. If you cannot do a restore, all the backups you have are useless.

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  • Can anybody suggest a good third party software?

    I was trying t go with redgate. ANy advise please.

  • Beginner_2008 (1/10/2013)


    Can anybody suggest a good third party software?

    I was trying t go with redgate. ANy advise please.

    RedGate SQL Backup is a good product. Not sure what that has to do with the original question, though.

    - Gus "GSquared", RSVP, OODA, MAP, NMVP, FAQ, SAT, SQL, DNA, RNA, UOI, IOU, AM, PM, AD, BC, BCE, USA, UN, CF, ROFL, LOL, ETC
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