Skip to main content

Virtualisation – An Introduction

For the last two years or so, in one capacity or another I have been running SQL Server in virtual land and I wanted to start writing some blog posts on the subject .

I thought I would start providing  a definition of virtualisation and then I thought better of it and I decided to leave it for the virtualisation experts, Scott Lowe in his book Mastering VMware VSphere 4 (you can find his blog here) provides a great definition of virtualisation:

“Virtualisation is the abstraction of one computing resource from another computing resource...when most information technology professionals think of Virtualisation , they think of hardware Virtualisation : abstracting the operating system from the underlying hardware upon which it runs and thus enabling multiple operating systems to run simultaneously on the same physical server.”

So the crux of virtualisation is  thus…You have one ( more likely many) relatively powerful server that act as the physical hosts with a hypervisor technology installed and from that setup  you have enough resources to run many virtual' machines (VMs) all sharing the hosts (physical servers) resources.

I assume you are reading this as a SQL Server professional thinking about running SQL Server in a virtual environment. My initial thought about virtualisation was “It might work for small web servers and applications server but it won’t be suitable for my resource hungry SQL Servers.” but I have come around to the idea of virtualisation and I don’t think that anymore.That said it is not necessarily true that virtualisation will suit all SQL Servers so the answer to the question “Should I virtualise  my SQL Servers?” like the answer to most DBA questions  “It depends!” Brent Ozar (Blog|Twitter) has some great articles and posts on his blog about why you should and why you shouldn’t virtualise SQL Server

Why Would You Virtualize SQL Server?

Reasons Why You Shouldn’t Virtualize SQL Server

If you are thinking about or researching running SQL Server on a virtual platform I recommend checking out Brent’s blog as a place to start.

So to the virtualisation software…In truth I have not got down to the nitty gritty of installing and setting up the virtualisation software myself, that has fallen to the sys and SAN admins. My experience has been with VMware’s ESX although Microsoft have a Hypervisor offering in the form of HyperV and XEN also have an open source hypervisor.

The main benefit of virtualising SQL Server, any server for that matter is you can greatly reduce the physical servers in your data centre thus reducing your power consumption and also reduce the heat (and cooling needed) generated by your server farm…which in turn can result in lower costs and reduced carbon foot print. As a DBA you will be concerned about getting the same performance from your virtual servers as your bare metal servers. From my experiences thus far I have got near enough the the same performance from a virtually provisioned server compared to a bare metal box

You also get a lot more flexibility with virtual hardware, servers can be provisioned very quickly at very little cost.

As I have said there are many benefits of virtualisation and some drawbacks its important to consider both sides when making a decision to virtualisation a SQL Server box.


Popular posts from this blog

SQL Server 2012 and Virtual Service Accounts

This post is written by David Postlethwaite
If you are using SQL Server 2012 you will probably have noticed that the default account for the SQL services has changed from that used in previous versions. With SQL 2005 and 2008 the default account for SQL service and SQL Agent service was “NT Authority\System”. This is one the built in accounts on a Windows machine, managed by the machine and selectable from a dedicated dropdown list

The Network Service account was introduced in Windows 2003 as an alternative to using the LocalSystem account, which has full local system privileges on the local machine, a major security concern.
The Network Service has limited local privileges easing these security concerns but when many services on a machine use the Network Service account it becomes harder to track which service is actually accessing resources and performing actions, because all the services are using the one Network Service account.
Also, this account, by default, has sysadmin per…

Always Encrypted

By David Postlethwaite

Always Encrypted is new features in SQL Server 2016 and it is also available in Azure SQL Database. Here you can encrypt columns in a table with a master key and a certificate so that they will appear as encrypted strings to those who don’t have the required certificate installed on their pc.
Once the certificate is installed on the computer then the unencrypted data can then be seen as normal.

The data passes from database to your application as the encrypted value, only the application with the correct certificate can unencrypt the data so it is secure across the wire. This will go some way to resolving the concern of people worried about putting their sensitive data on a shared server in the cloud such as Microsoft Azure and accessing the data across the Internet.

At the time of writing Always Encrypted is only supported with ADO.NET 4.6, JDBC 6.0 and ODBC 13.1 but expect other driver to become available.

The calling application (including SSMS) must also hav…

How to Setup Kerberos Correctly

David was in Copenhagen this weekend delivering his Kerberos talk Taming the Beast: Kerberos for the SQL DBA to SQL Saturday Denmark. I have had a quick chat with him via email since he got back and he said he had a great time. The event was very well attended with 280+ attendees and his talk was well attended.

I think David is planning submitting a few sessions to SQL Saturday events in Europe in the next few months so look out for him there and we'll keep you posted as to his whereabouts when schedules get finalised later in the year.

David has pre-recorded his Kerberos talk. You can watch on you tube and I have also embedded it in this post if you want to see what his kerberos talk  covers...

If we can help you with a SQL Sever problem visit our SQL Server Consulting page or contact us