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Category: Administration

Migrating TFS

Published 2016-04-21 by Kevin Feasel

Dave Mason has notes on migrating TFS from one server to another:

If you are migrating, but want to keep the databases on SQL 2012 Express, then you can skip this part. I wanted them moved to my SQL 2014 instance. So I did a traditional backup/restore from SQL 2012 Express to SQL 2014. I took new backups of the SQL 2014 databases, and then uninstalled SQL 2012 Express. Then I had to configure TFS to connect to a different SQL instance. Within the web.config file (%ProgramFiles%\Microsoft Team Foundation Server 12.0\Application Tier\Web Services\web.config), I found an application setting named “applicationDatabase”. I made a backup copy of web.config first, then I changed the “applicationDatabase” value. It should be in a recognizable format if you’re familiar with SQL Server connection strings. You can also make this change within IIS. It was there that I noticed a few other settings that contained SQL connection strings. Check out the following in IIS and change settings as needed:

Dave has lots of screen shots to make the process easier to understand, but my main takeaway is that for the most part, migrating TFS  is a huge pain…

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Max Server Memory

Published 2016-04-18 by Kevin Feasel

SQL Sasquatch explains what “max server memory” does and how it relates to private bytes:

Well, there’s obviously a relationship between private bytes and “total server memory”.  The peaks and valleys occur at the same time.   But there’s a delta between them, and the delta isn’t constant.

The difference between private bytes and “total server memory” is pretty well confined, too – not varying more than 10 mb in this interval.

Read the whole thing.

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Against DBCC Commands

Published 2016-04-15 by Kevin Feasel

Erik Darling doesn’t like (most) DBCC commands:

Not what they do, just that the syntax isn’t consistent (do I need quotes around this string or not?), the results are a distraction to get into a usable table, and you need to write absurd loops to perform object-at-a-time data gathering. I’m not talking about running DBCC CHECKDB (necessarily), or turning on Trace Flags, or any cache-clearing commands — you know, things that perform actions — I mean things that spit tabular results at you.

I completely agree.  One of the nicest things about SQL is that I can use the same syntax to read metadata that I can data.  DBCC commands are a jarring difference.

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Azure Status Alerts

Published 2016-04-15 by Kevin Feasel

Ron Dameron has built Outlook rules for Azure status alerts:

I do have alerts set up on the Azure portal and in Application Insights to notify me when availability or performance thresholds are violated but I also need to know if there is a global or regional issue that might affect our app so that I can respond and notify the staff when appropriate. Azure status changes are reported on the Azure Status web page.

The following will describe how to use the Azure Status page RSS feeds and Outlook rules for notification if things go sideways in Microsoft Azure.

This is a good use of Outlook’s built-in RSS reader.

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Change Management Template

Published 2016-04-14 by Kevin Feasel

Kendra Little walks through a fairly simple but very useful change management template:

Good Change Management makes your team smarter. When you change things a lot, things are going to break sometimes. If you’ve done a good change request, you’ll know exactly what to do when something breaks: either you’ll roll the change back, or have a Plan B to execute on. Good change requests also mean that business owners understand the risks of the changes and have approved them, and that teammates have reviewed them: good changes aren’t done in isolation.

Change Management isn’t just for IT. If you’re a developer who deploys changes to production, you need this as well.

Change management doesn’t need to be a complex endeavor.  It should, however, give you enough information to save yourself if things get crazy.

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Retrieving WMI Information

Published 2016-04-06 by Kevin Feasel

Dave Mason shows how to retrieve WMI information (perhaps the “wrong” way):

In another post I explored a way to run WMI queries from tsql (sort of). Let’s do it again. The script below enables xp_cmdshell, runs WMIC.exe (capturing the output to a temp table), shreds the XML, returns a result set of columns and rows, and disables xp_cmdshell. If you’re adventurous and daring, run the script in a test environment.

With Powershell, as Dave mentioned, this really isn’t the best way to do the job, but there are times when you aren’t able to use Powershell.

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Drop Column In SQL Server 2012/2014

Published 2016-04-04 by Kevin Feasel

Aaron Bertrand explains a bug in SQL Server 2012 and 2014 which can crop up after dropping a column:

A fix has been published for SQL Server 2012 (SP2 and SP3), and one is coming for SQL Server 2014 (RTM and SP1) – though in this most recent update, SQL Server 2014 was removed from the list of affected versions (not sure it was accurate to remove those). I will update this space once the next 2014 CUs are released, but for now you should plan to rebuild tables after dropping columns as a matter of course and, more importantly, as part of the same maintenance operation.

This is a good reason to stay up to date on CUs.

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Securing Plaintext Passwords

Published 2016-03-30 by Kevin Feasel

John Morehouse shows you how to fix plaintext password storage when you can’t fix the application:

Once the data has been encrypted, we can move forward with creating a new view that will be used to “head fake” the application. The view is named the same as the original table therefore the change is seamless to the application.  The application doesn’t know if it’s calling a table or a view so that’s why this works.

You should never store passwords in plaintext.  You should almost never store passwords in a reversable format (i.e., encrypted).  The primary case in which I can see storing passwords encrypted rather hashed is if you have automated systems (or non-automated technicians) which need passwords to authenticate somewhere.  Even then, there’s a lot of value in using OAuth tokens.  But if you can’t get around any of this, John’s solution does remove the really bad decision of leaving passwords in plaintext.

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Availability Groups And VMs

Published 2016-03-30 by Kevin Feasel

John Martin looks at combining Availability Groups with a virtualized environment:

Much of the time there is a systems team and a DBA team, and when the DBAs need to build out a new set of SQL Servers, they request X number of virtual servers from the systems team. The servers are handed over and the DBA team works its magic, and then we have our Failover Cluster Instance or Availability Group High Availability solution. But, is it really Highly Available?

The reason I ask is twofold:

  • Which physical hosts are your Virtual Machines are located on?
  • Which data stores are your virtual disks are located in?

If the answer to either of these questions results in the same answer for any of your Virtual Machines in an Availability Group, or Failover Cluster Instance for that matter. Then you potentially have a massive flaw in your implementation that can affect availability.

The moral of the story is to communicate with the network administrators and SAN folks.

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Memory Pressure

Published 2016-03-28 by Kevin Feasel

Thomas Rushton walks us through determining if there’s memory pressure on an instance:

If you’ve been paying attention, you’ll have noticed that I’ve done the rownumbering in reverse order, and added a dummy (RowNum 0) field at the top of the list – this is to make sure that, if the most recent record is a RESOURCE_MEMPHYSICAL_LOW record, that we can get results that include that value.

This all looks OK in theory. But we’re still getting stupidly high values for the SecondsPressure field, and wait – what’s this? Multiple ring buffer records with the same ID?

More importantly, he shows us how bad the situation is:  is this something that happened for a couple of seconds, or is it persistent?  This is a great walkthrough.

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