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Category: Administration

Validating Database Mail

Published 2017-11-15 by Kevin Feasel

Frank Gill has a script to validate that your database mail settings are valid:

In my last post, I shared a script to automate the migration of SQL Server Database Mail settings. In this post, I show how to send test e-mails from all Database Mail profiles on an instance. The migration I was working on contained 21 Database Mail profiles. The following script will send a test e-mail from each profile to confirm successful configuration. I hope you can put this code to use in your migrations.

Click through for the script.

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Upgrading A Cluster To Windows Server 2016

Published 2017-11-14 by Kevin Feasel

Ryan Adams shows how to upgrade a failover cluster running Windows Server 2012 R2 to Windows Server 2016 without having to start from scratch:

Starting in Windows Server 2012 R2 you now have a way to upgrade a cluster to Windows 2016.  The best part is it’s not an OS upgrade, but a rebuild.  The magic is that you can join a Windows 2016 server to a Windows 2012 R2 cluster.  You can upgrade your cluster with as little as one failover and thus very little down time.  Everything stays in compatibility mode until all nodes are upgraded to Windows 2016 and then you upgrade the cluster functional level.  This is great news for those of us running FCIs or AGs.

Click through for a listing of steps and a video.

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Offline Installation Of SQL Server 2017 ML Services

Published 2017-11-13 by Kevin Feasel

Jan Mulkens shows how to install SQL Server 2017 Machine Learning Services when your the server hosting SQL Server doesn’t have outbound internet access:

That’s when you remember it… Your server isn’t connected to the internet!
Pretty normal, but in your enthusiasm you completely forgot that SQL Server needs to download some binaries for the R and Python components you so desperately want on your precious machine!

Luckily, the installer comes to your rescue and shows you where to download those binaries it needs.
Turns out however… This link only is for one R component and the installer won’t let you pass to the next screen!

Read on for the answer.

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Backup-Related Instance Settings

Published 2017-11-10 by Kevin Feasel

Monica Rathbun explains a few instance-level backup properties:

Default backup media retention in days. Now the first things that comes to my mind is that “hey this is a cleanup job” SCORE! Thinking that maybe this will auto delete old backups. After all isn’t that what retention means? NOPE, not in this case.

In this case it’s just a number of days before that a backup media can be OVERWRITTEN. If the DBA goes to overwrite the media before those days it will give a warning message. You’ll note in every back up action you do the RETAINDAYS option is filled in. In this case it will always reflect to 90 now that we have changed it. In general, this a pointless option to me. I don’t normally OVERWRITE backup media. To me this was more relevant when Tapes were used and disk were harder to come by, so I leave it alone.

Read on for more settings.

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Migrating DBMail Settings

Published 2017-11-08 by Kevin Feasel

Frank Gill has a T-SQL script to help with database mail migration:

This week, I was working on a migration for a client.  The migration was moving databases from a stand-alone instance to a two-node Availability Group.  When it came to moving the Database Mail settings, I discovered they had 21 sets of profiles and accounts.  Not wanting to manually create 42 Database Mail profiles, I set out to automate the process.  A web search yielded this blog post by Iain Elder. This script does what I was looking for, but would only generate settings for a single Database Mail profile.  Using Iain’s code as a starting point, I modified it to create Database Mail settings for all profiles on an instance.  The script is listed below. I hope this simplifies your SQL Server migrations.

Click through for Frank’s script, and you might also be interested in Iain Elder’s script, linked above.

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Soft-NUMA Doesn’t Limit MAXDOP

Published 2017-11-07 by Kevin Feasel

Lonny Niederstadt tests whether soft-NUMA forces MAXDOP = 1:

I mentioned that I was planning to set up a soft-NUMA node for each vcpu on a 16 vcpu VM, to evenly distribute incoming connections and thus DOP 1 queries over vcpus.  Thomas Kejser et al used this strategy to good effect in “The Data Loading Performance Guide”, which used SQL Server 2008 as a base.
https://technet.microsoft.com/en-us/library/dd425070(v=sql.100).aspx

My conversation partner cautioned me that leaving this soft-NUMA configuration in place after the specialized workload would result in DOP 1 queries whether I wanted them or not.  The claim was, effectively, a parallel query plan generated by a connection within a soft-NUMA node would have its MAXDOP restricted by the scheduler count (if lower than other MAXDOP contributing factors).  Though I wasn’t able to test at the time, I was skeptical: I’d always thought that soft-NUMA was consequential to connection placement, but not to MAXDOP nor to where parallel query workers would be assigned.

I’m back home now… time to test!!

Read on for the test.

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Picking Azure VM Sizes

Published 2017-11-07 by Kevin Feasel

Glenn Berry helps us pick the right-sized Azure VM for a SQL Server installation:

A common issue with Azure VM sizing for SQL Server has been the fact that you were often forced to select a VM size that had far more virtual CPU cores than you needed or wanted in order to have enough memory and storage performance to support your workload, which increased your monthly licensing cost.

Luckily, Microsoft has recently made the decision process a little easier for SQL Server with a new series of Azure VMs that use some particular VM sizes (DS, ES, GS, and MS), but reduce the vCPU count to one quarter or one half of the original VM size, while maintaining the same memory, storage and I/O bandwidth. These these new VM sizes have a suffix that specifies the number of active vCPUs to make them easier to identify.

For example, a Standard_DS14v2 Azure VM would have 16 vCPUs, 112GB of RAM, and support up to 51,200 IOPS or 768MB/sec of sequential throughput (according to Microsoft). A new Standard_DS14-8v2 Azure VM would only have 8 vCPUs, with the same memory capacity and disk performance as the Standard_DS14v2, which would reduce your SQL Server licensing cost per year by 50%. Both of these Azure VM SKUs would have the same ACU score of 160.

Glenn is, as always, a font of useful information.  Go read the whole thing.

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Error Handling On SQL With Linux

Published 2017-10-31 by Kevin Feasel

Anthony Nocentino explains Linux error codes and systemd behavior for SQL on Linux:

Now in the output above, you’ll notice a bolded line. In there, you can system that systemd[1] receives a return code from SQL Server of status=1/FAILURE.  Systemd[1] is the parent process to sqlservr, in fact it’s the parent to all processes on our system. It receives the exit code and immediately, systemd initiates a restart of the service due to the configuration we have for our mysql-server systemd unit.
What’s interesting is that this happens even on a normal shutdown. But that simply doesn’t make sense, return values on clean exits should return 0. It’s my understanding of the SHUTDOWN command, that it will cause the database engine to shutdown cleanly.

On the development side, there aren’t many differences between SQL on Linux versus SQL on Windows (aside from things which haven’t yet made the move); on the administration side, there are some interesting differences.

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Stress Testing SQL Server

Published 2017-10-27 by Kevin Feasel

Jes Borland shows how to use ostress to perform load testing against a SQL Server instance:

Ostress allows you to specify one file, or a folder that contains multiple files, to run. You can also specify a number of connections to be made to the database, to simulate multiple users or applications running the same query. Each connection can then run the file one or more times.

The next thing you’ll need is one or more .sql files that the tool will run.

To run a load test, you’ll open RML cmd prompt and enter your command.

Ostress isn’t as nice as a replayable trace for generating production loads, but it’s an easy method to stress test a server.

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