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Category: Administration

HDFS Cheat Sheet

Published 2016-11-25 by Kevin Feasel

Tim Spann has produced a guide for HDFS shell commands:

There are number of commands that you may need to use for administrating your cluster if you are one of the administrators for your cluster.   If you are running your own personal cluster or Sandbox, these are also good to know and try. Do Not Try These In Production if you are not the owner and fully understand the dire consequences of these actions.   These commands will be affecting the entire Hadoop cluster distributed file system.  You can shutdown data nodes, add quotas to directories for various users and other administrative features.

Many of the commands in this list should be familiar if you know much about Linux or Unix administration, but there are some Hadoop-specific commands as well, like moveFromLocal and moveToLocal.

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HAL0003

Published 2016-11-25 by Kevin Feasel

Kenneth Fisher is on a mission:

  • HAL0001 randomly stopped you from making DDL changes.

  • HAL0002 stopped you from using NOLOCK in code.

  • HAL0003 will not let you touch a given table (DiscoveryOne as it happens) and will disable your login and kill your connection if you try.

He’s got a ways to go, but I applaud his long-term vision.

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Uninstalling SQL Server 2016 SP1

Published 2016-11-25 by Kevin Feasel

David Alcock sounds an important note:

All of that is very good however a word of warning has been issued from the MSSQL Tiger Team if you are using SP1 on the “lower” version:”you might see some unforeseen errors or databases might even be left in suspect state after uninstallation of SQL Server 2016 SP1. Even worse would be if the system databases are using new features for example, partitioned table in master database, it can lead to SQL Server instance unable to start after uninstalling SQL Server 2016 SP1″.

This makes sense:  if you’re using new functionality and try to revert back to a version without that functionality available, there could be an issue.  David links to a test script you can use to see if your database is using any new features.

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Locks In Sp_configure

Published 2016-11-23 by Kevin Feasel

Kendra Little discusses the locks entry in sp_configure:

Each lock uses 96 bytes of memory. On the instance in question, 25,000 locks  = 2,400,000 bytes.

That’s only 2.3 MB of memory devoted to locks. Even though 25K  sounds like a lot, the memory footprint for that is pretty darn small.

I checked back with our questioner, and their instance has 32GB of memory. That’s a pretty small amount in the grand scheme of things (as of SQL Server 2014, Standard Edition can use up to 128GB of memory for the Buffer Pool), but 2.3 MB isn’t anything to worry about, percentage wise.

Read on for advice if you’re seeing your SQL Server instance take a very large number of locks.

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Buffer Pool TreeMap

Published 2016-11-23 by Kevin Feasel

Aaron Nelson has a post on using Powershell to visualize contents in the buffer pool:

On Monday Chrissy LeMaire & I Did a session called “SQL Server Cmdlets and Community Involvement” for the PowerShell 10 Year Anniversary all-day event on Channel9 on MSDN. If you jump to the 18 minutes 30 second mark of that video you’ll see me showing how to look at the Buffer Pool of your SQL Server instance, first with the Out-GridView cmdlet, then I used a function from PowerShell MVP Boe Prox ( b | t ) called Out-SquarifiedTreeMap like so:

Read on to get a link to the code.

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High Availability On Linux

Published 2016-11-22 by Kevin Feasel

David Bermingham looks at high availability within SQL Server on Linux:

With Microsoft’s recent release of the first public preview of MS SQL Server running on Linux, I wondered what they would do for high availability. Knowing how tightly coupled AlwaysOn Availability Groups and Failover Clustering is to the Windows operating system I was pretty certain they would not be options and I was correct.

Well, the people over at LinuxClustering.Net answered my question on how to provide high availability failover clusters for MS SQL Server v.Next on Linux with this great Step by Step article.

The linked article is amazing.  It uses a piece of third-party software to perform clustering, so it’s not a free solution.  We’ll see if Microsoft is able to build in a full HA solution in the first version of Linux-supported SQL Server, but if not, it looks like there’s an alternative.

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Power BI Admin Portal

Published 2016-11-18 by Kevin Feasel

Melissa Coates looks at the Power BI tenant settings in the admin portal:

Keep in mind that these selections apply to all users across the entire tenant. At this time we can’t control them by groups or anything of that nature.

In addition to the above settings for controlling user experience, the Admin Portal is also the place for viewing usage metrics which are helpful for determining who runs what how often (it’s not everything we could possibly want to know, but it’s a good start). The other two options, manage users and audit logs, redirect you over to the Office 365 Admin Center.

Another week, another few dozen Power BI additions…

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SQL Server In Containers

Published 2016-11-16 by Kevin Feasel

Andrew Pruski shows how to install Docker on Windows Server 2016 and pull down a SQL Express container:

But what about connecting remotely? This isn’t going to be much use if we can’t remotely connect!

Actually connecting remotely is the same as connecting to a named instance. You just use the server’s IP address (not the containers private IP) and the non-default port that we specified when creating the container (remember to allow access to the port in the firewall).
Easy, eh?

Containers are great, though I do have trouble wrapping my head around containerized databases and have had struggles getting containerized Hadoop to work the way I want.

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Get-DbaTcpPort

Published 2016-11-15 by Kevin Feasel

Steve Jones looks at one Powershell function inside dbatools:

I like using PoSh for some tasks, especially when I don’t have an easy way to do something in SSMS or want to run a task across a variety of instances. In this case, as I glanced through the September updates, I found a good one.

Get-DbaTcpPort

I don’t love the mixed naming, and I’ll get used to it, but I do love the autocomplete in PoSh.

Steve has lots of screenshots walking you through this function.

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