Voice of the DBA

Category: Editorial

  • VMs for Development

    Here’s the scenario: you have gotten a few consulting jobs and have a couple clients. This could be your full time employment, or a side job that you perform away from another employer. You want to watch your budget, ensure you can work efficiently, and handle whatever requirements your clients may send your way. This week’s question is:

    How do you set up your virtual environment at home?

    I think the idea of using Virtual Machines (VM) is a given these days, but do you have one VM with all your tools in it? Do you use separate VMs for each client? What about licensing? Those can be complex questions for many people, especially if your employer does not provide you with multiple license keys.

    I hope that you are using VMs as having multiple computers isn’t practical these days, especially as the cost of power rises. A relatively small, inexpensive desktop computer can run 5, or even 10, VMs to simulate a variety of environments. I’ve seen some creative uses of hypervisors and other software to simulate clusters, SANs, and even multiple domains on one host.

    Let us know this week if you have some good tricks that can help someone get started with virtual machines, building a lab, choosing hardware, or easily configuring networking for their own learning efforts. Tell us what software you use, and if you don’t mind sharing cost data, I’m sure others would appreciate the information.

    Steve Jones

    The Voice of the DBA Podcast

    Listen to the MP3 Audio ( 1.9MB) podcast or subscribe to the feed at iTunes and Mevio . feed

    The Voice of the DBA podcast features music by Everyday Jones. No relation, but I stumbled on to them and really like the music. Support this great duo at www.everydayjones.com.

  • What is Continuous Integration for Databases?

    I have a talk that I give on Automated Build and Test for databases. This was put together by one of the engineers at Red Gate Software, and I’ve presented it at a number of events. I enjoy it, and it’s one of those presentations that really gets people thinking. I enjoy getting people to think about software, and there are always good questions that come out of the session.

    The talk is essentially about how to set up continuous integration for databases. Continuous Integration is an extension of the daily build, which companies have been using for years to try and ensure some discipline in their software development practices. They want to limit the amount of code that can potentially break software.  The whole idea is to test changes developers commit to version control as quickly as possible and give feedback developers immediately so developers can fix issues while the issue is fresh in their minds.

    For databases, this can be a challenge. We have this stuff called data that has to be maintained between, during, and after builds. We can’t drop our structures and reload them as a developer does with an executable or DLL. As we work in a CI environment, we need to handle new objects, as well as alterations to existing structures. That means our scripts and code need to handle creation as well as upgrade scripts.

    This means that a CI process for databases must not only check out the DDL code from a Version Control System (VCS), but it must also handle the CREATE or ALTER code based on the state of the database. You can always build a database from scratch in your CI process, or you can restore a known version (usually the last version) and apply upgrade scripts. The way this happens depends on how you version your DDL code in a VCS and how your build process is structured.

    At Red Gate, we’ve built a number of scripts to help with this process for various CI servers. We have articles that discuss CI for Team City, Jenkins, Bamboo, and probably more by the time this piece appears. We’ve learned a lot about CI over the last few years and we are trying to share both our knowledge and code with you, as well as incorporate those ideas into our products.

    Whether you use our products or not, we do believe that you will build better software if you implement CI. We just know that we can make the process a lot smoother with our tools for developers and DBAs.

    Steve Jones

    The Voice of the DBA Podcast

    Listen to the MP3 Audio ( MB) podcast or subscribe to the feed at iTunes and Mevio . feed

    The Voice of the DBA podcast features music by Everyday Jones. No relation, but I stumbled on to them and really like the music. Support this great duo at www.everydayjones.com.

  • How Often Do I Backup my Log?

    Do you know how often to back up your transaction log in SQL Server? Most of us have stock answers, hopefully answers that have time intervals like every hour. I worry that most people have a time interval of “never” because their answer is “I make full backups and don’t need to backup logs” or “What’s a transaction log?” That’s a different discussion and if those are your answers, I have an article for you to read.

    Managing a transaction log is a bit tricky and not straightforward. I think far too many people manage their logs based on the space they are trying to maintain on disk. However that’s not the way you decide when to back up logs. The way you decide how to back up a log has nothing to do with space. It’s best stated in this quote from Gail Shaw: “the log backup interval should be less than the allowable data loss for the system.”

    Simply put, decide how much data you can afford to lose. Or how much loss will exceed your tolerance for being yelled at. That’s your log backup interval. Make a log backup after that much time passes. Schedule that interval into your maintenance operations and observe how big the log backups are. That will determine your log size, not the other way around.

    As with most guidance and advice, this is based on a time and place in the platform’s lifecycle. This is the advice I’ve used from SQL Server 7 to 2012, but it’s subject to change, so make sure it’s still valid if you’re reading this in 2020.

    And, of course, make sure that you also understand how to restore these backups in case you do have an issue. That’s probably the most important thing to know.

    Steve Jones

    The Voice of the DBA Podcast

    Listen to the MP3 Audio ( 2.5MB) podcast or subscribe to the feed at iTunes and Mevio . feed

    The Voice of the DBA podcast features music by Everyday Jones. No relation, but I stumbled on to them and really like the music. Support this great duo at www.everydayjones.com.

  • The Data Platform Vision

    Recently the Microsoft Data Platform blog published a piece on what drives Microsoft’s vision. It’s an interesting look at the ways in which data is being used in some businesses as well as the variety of types of situations that must be dealt with. There is this idea that the value derived from having lots of different data was once only used by specialized companies or applications. However today, it’s being more widely analyzed and accepted by more businesses. Of course, the vision is that Microsoft can help those businesses.

    In the cloud.

    I know this piece is more marketing than technical, but I have concerns that Microsoft is not driven by what customers want and need, but is instead seeking to drive customers to their own tooling and offerings in the Azure cloud. While I do like many things about the cloud and think it has a place in the future of many companies, I also think that there are still lots of opportunities, as well as demand from customers, for on-premises solutions.

    I worry that the focus of Microsoft, which can be tightly bound in one idea as they eye more sales revenue, is driven with the idea that everyone, and all applications, will some day be in the cloud. I can’t see that in the future for many businesses, and certainly hope that Microsoft recognizes this. Otherwise many of our hybrid solutions that push some data into the cloud might be backed by PostgreSQL or some other platforms as the on-premises database.

    Steve Jones

    The Voice of the DBA Podcast

    Listen to the MP3 Audio ( 2.2MB) podcast or subscribe to the feed at iTunes and Mevio . feed

    The Voice of the DBA podcast features music by Everyday Jones. No relation, but I stumbled on to them and really like the music. Support this great duo at www.everydayjones.com.