All About RAID

I have been asked about RAID a lot of times at the interviews previously. My mindset was quite blurred at a couple of times. But now, I am asking myself, ‘What is RAID?’, ‘What are RAID levels?’ and ‘How do you configure RAID level for SQL Server?’ In this post, I am starting with the basic concept of RAID.

What is RAID?

RAID shorts for Redundant Array of Independent (or Inexpensive) Disks. It’s the combination of multiple disk drives into large, high performance logical disks, which allows the same data to be redundantly stored in the different places crossed the physical disks. As the result, it will increase fault tolerance, data availability, system reliability and I/O performance.  

What are RAID levels?

The common RAID levels used for SQL Server are RAID 0, 1, 5 0+1 or 1+0.

Finding and Troubleshooting SQL Server Permissions

It can be very tricky to troubleshoot user permissions on SQL Server. As SQL Server DBA, we are quite often questioned by users about what permissions they’ve got.  The permissions can be granted on server, database, schema and database object level (such as table, store proc, views, functions, and etc). To avoid dig through many screens or levels in management studio, fn_my_permission, as a built-in table value function from SQL Server 2005, provides the list of all the permissions effectively granted to the principle on a securable.

Before starting the permission checks, your login needs to be an account that has sysadmin role.

To list all permissions on server:

If login isn't specified, it shows what permissions the caller has by default.

                                                                       

EXECUTE AS LOGIN = 'Domain\UserLogin'

SELECT * FROM fn_my_permissions(NULL, NULL)

REVERT

Revert is to switche the execution context back to the caller of the last EXECUTE AS statement

Or alternative use

SELECT * FROM fn_my_permissions(NULL, 'SERVER')

Scheduling Server Side Trace (Profiler) For Deprecated Features

I was trying to use profiler to trace deprecated features in a SQL Server 2005, before it’s migrated from 2005 to 2008. And also capturing the use of deprecated features in different time period during a day was required, especially for those SQL queries that run over night. However SQL Server Profiler doesn’t provide a build-in scheduling option, so I decided to use SQL command to schedule an agent job, so that the profiler trace can automatically start.

Firstly, Use SQL Profiler to create the trace definition

1. Start SQL Profiler and select File > New Trace. Specify the events, columns, filters you want in your trace.
2. Start the trace and then stop it.
3. Export the definition. Click File > Export > Script Trace Definition > For SQL Server 2005. Save the scripted trace as ‘*.sql’.
   Note: For SQL Sever 2000 and 2008 choose the appropriate output type.

Secondly, Create a store procedure to set up profiler trace.

Here, I am using tracing deprecated features as a sample.

Success Quality Life (SQL) Adventure

This is my first post, and I wanted to use it to set the tone for the rest of this site. I am sitting next my boyfriend Nick, in my cutty blue underwear, and looking out the window at Clifton, Bristol where I lived for the last 5 years in the UK. This is how the blogs are meant to be written.

I am feeling happy, as I write this, but there are still so much more that I want to achieve in my unpredictable future life. When I first time became a professional DBA at Nokia in 2009, I was excited and fascinated everything about database world. SQL doesn't just mean Structured Query Language as a database language to me. The deeper I look into database technology, the more power and flexibility I find in my own life. I deeply believe this is the right path for me to pursuit my personal ambitions.

Let me start Success Quality Life Adventure just from here....