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Category: Backups

Testing Backups With dbatools

Published 2017-09-15 by Kevin Feasel

Constantine Kokkinos shows off a dbatools cmdlet to test the last full backup:

This:

  • Defines a list of two servers (PowerShell lists are as easy as “”,””)

  • Pipes them to the Test-DbaLastBackup command.

  • Which then:

    • Gathers information about the last full backups for all of your databases on that instance.

    • Restores the backups to the Destination with a new name. If no Destination is specified, the originating server will be used.

    • The database is restored as “dbatools-testrestore-$databaseName” by default, which you can change with the -Prefix parameter.

    • The internal file names are also renamed to prevent conflicts with original database.

    • A DBCC CHECKTABLE is then performed.

    • And the test database is finally dropped.

Pretty snazzy.

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Considerations With Third-Party Backup Tools

Published 2017-09-13 by Kevin Feasel

Gianluca Sartori gives us a laundry list of potential problems with third-party database backup solutions:

2. Potentially dangerous separation of duties
Backup tools are often run and controlled by windows admins, who may or may not be the same persons responsible for taking care of databases. Well, surprise: if you’re taking backups you’re responsible for them, and backups are the main task of the DBA, so… congrats: you’re the DBA now, like it or not.
If your windows admins are not ok with being the DBA, but at the same time are ok with taking backups, make sure that you discuss who gets accountable for data loss when thing go south. Don’t get fooled: you must not be responsible for restores (which, ultimately, is the reason why you take backups) if you don’t have control over the backup process. Period.

There is plenty of sound advice in this post.  These points also apply to roll-your-own solutions as well, but the main focus is on enterprise backup tools, which are in many cases surprisingly shoddy.

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Errors With Invalid Backup Location

Published 2017-08-30 by Kevin Feasel

Adrian Buckman shows the types of errors you should expect when your default backup location is invalid:

Recently I was looking through the error log on one of my test machines and I spotted some unusual errors:

SQL ERROR: 3634 – The operating system returned the error ‘3(The system cannot find the path specified.)’ while attempting ‘DeleteFile’
SQL ERROR: 18272 – During restore restart, an I/O error occurred on checkpoint file (operating system error (null)). The statement is proceeding but cannot be restarted. Ensure that a valid storage location exists for the checkpoint file.

At first I assumed that I may have tried restoring a database to a location that did not exist but this was not the case, the actual issue was with SQL Server’s Default Backup Location.

Read on for the full explanation.

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When Database Restoration Leaves The Source In Recovery

Published 2017-08-15 by Kevin Feasel

David Fowler shows how you can restore a database to a new database and leave the original in recovery mode:

If you ever restore a backup to a new database, there’s something that you should probably be aware of otherwise you could easily find yourself in this situation.

Let’s have a look at what happens when we try to restore a copy of the SQLUndercover database using SSMS.  We’re going to kick this off by right clicking on ‘SQLUndercover’ and selecting restore database.

Read this to avoid a panic attack.

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Backing Up That Linux-Based Database

Published 2017-08-09 by Kevin Feasel

David Klee shows how to back up a SQL Server on Linux database over the network:

As of SQL Server 2017 RC2, we’ll want to accomplish it in a way that is transparent to SQL Server. (Depending on the RTM version whenever it is released, I might change the recommendation on this.) To do this, we’ll want to create a folder on the local file system that actually maps to a remote network share for SQL Server backups.

SSH into your server without elevated privileges at this point.

The network share is presented from a Windows server with the SMB protocol. Linux can connect to this using a compatible protocol called CIFS, or Common Internet File System. We’ll need to install the packages so we can natively connect. On Ubuntu and other Linux distros, the easiest is with the cifs-utils package. To install from the package manager is as simple as this.

Sadly, that credentials file cannot be encrypted.

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Querying MSDB For Backup Information

Published 2017-07-28 by Kevin Feasel

Lori Brown shows how to query the msdb database and get information on backups, including whether the backups are compressed:

We recently started using a third party software to do our in-house SQL backups so that the backup files are stored in a redundant and safe place. To confirm that the software was indeed compressing backups as it stated it would, we wanted to see what each backup size actually was in SQL so that we could compare that to what the software was telling us.

SQL stores lots of handy backup information in msdb in the backupset and backupmediafamily tables.

There’s some useful information in these tables, though make sure you clean them up regularly or else msdb can become enormous.

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Tracking Database Restoration-Related Errors

Published 2017-07-18 by Kevin Feasel

Adrian Buckman has a script which tracks error messages related to database restorations:

In one of my previous posts I went over a scenario where an Auto restore job was logging Restore errors to a table and the error that was being inserted was ‘3013 – RESTORE LOG is terminating abnormally’ and this was due to SQL Server only providing the Last most error produced which is stored within ERROR_NUMBER() and ERROR_MESSAGE() at point of error.

I found this error less than useful so I set out to try and log something more meaningful , which I ended up doing for the specific error (4305) which was being encountered at the time, but I wanted to make this better and less specific to the 4305 error.

This is a very interesting post and a good example of using built-in error handling functionality to help automate your processes.

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STOP Date Formats

Published 2017-07-13 by Kevin Feasel

Dave Mason notes that the STOPAT date option when restoring a log backup is temperamental:

There’s nothing I see in the documentation regarding the format for “time“. But there are a couple of examples, including this one:

RESTORE LOG AdventureWorks  
FROM AdventureWorksBackups  
WITH FILE=4, NORECOVERY, STOPAT = 'Apr 15, 2020 12:00 AM';

That string looks suspiciously like a US English date format. I suspect that wouldn’t work for languages that don’t recognize “Apr” as a month. And what if the date is displayed in one of the many date formats used outside of the US? Lets find out!

Dave tried 21 different date formats; click through for the results.

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Check Where That Backup’s Restoring To

Published 2017-07-12 by Kevin Feasel

Shane O’Neill “has a friend” who learned an important lesson about the database restore GUI:

GUIs are good for….

…discovery.

They give you the option to script out the configurations you have chosen. If my friend had chosen to script out the restore, rather then clicking “OK” to run it, maybe he would have caught this mistake when reviewing it – rather than overwriting the Live database with 2 week old data and spending a weekend in the office with 3 colleagues fixing it.

Plus if you ever want to ensure that you know something, try and script it out from scratch.

Read the whole thing; good thing that totally didn’t happen to Shane and was just his friend!

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Tracking Database Restorations

Published 2017-07-03 by Kevin Feasel

Erik Darling points out that figuring out when a database restoration occurs is much more difficult than you’d hope:

Astute SQL-ers may attempt to add a trigger to the restorehistory table over in msdb. It’s in the dbo schema, which might make you hopeful. We all know triggers in that pesky sys schema don’t do a darn thing.

You guessed it, restores get tracked there. So there’s, like, something inside SQL telling it when a restore happens.

Guess what, though? A trigger on that table won’t fire. Not FOR INSERT, not AFTER INSERT, and not nothin’ in between.

Read on for more things that don’t work…  Also check out the comments; I think Dave Mason has the best answer there.

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