SQL Server Hardware Requirements

In this article on SQL Server Hardware Requirements I will discuss the following two topics:

• Minimum Hardware Requirements
• Optimizing Hardware for SQL Server

When specifying your SQL Server hardware requirements always consider the following:

• The size of the database;
• Number of concurrent users;
• Transaction throughput;
• The operations that will be performed on the databases.

Minimum SQL Server Hardware Requirements

The following are Microsoft's © recommendations for the minimum SQL Server hardware requirements.

I will discuss the different Versions and Editions in the next article.

Processor:

Intel® or compatible Pentium 166 MHz or higher. Memory (RAM):

Enterprise Edition and Enterprise Evaluation Edition: 64 MB minimum, 128 MB or more recommended Standard Edition and Developer Edition: 64 MB minimum Personal Edition and Desktop Engine (MSDE 2000):

• 128 MB minimum on Windows XP
• 64 MB minimum on Windows 2000
• 32 MB minimum on all other operating systems

Disk Space:

Enterprise, Enterprise Evaluation, Standard, Developer, and Personal Editions require:

• 95 to 270 MB of available hard disk space for the database engine; 250 MB for a typical installation.
• 50 MB of available hard disk space for a minimum installation of Analysis Services; 130 MB for a typical installation.
• 80 MB of available hard disk space for English Query.
• Desktop Engine (MSDE 2000): 44 MB minimum

Optimizing SQL Server Hardware

I would recommend that for a production server that hosts your important most frequently accessed databases and for database that must have high availability that you upgrade the SQL Server hardware beyond the minimum specification in some cases to the highest specification that can produce.

This will help to prevent bottlenecks and poor system performance.

Processor: I would recommend that you "scale up" your server's processor and in some cases also "Scale out."

By "Scaling Up" to faster processors SQL Server will process queries faster. This will result in your end users seeing an improvement in performance.

Also it may be necessary to "scale out" your processors. According to Microsoft © SQL Server can support up to 32 processors on Symmetrical Multiprocessing (SMP) computers running on Windows 2000 Data Centre Server.

Scaling out multiple processors may improve fault tolerance and maybe necessary for some very large databases.

Disk Drives and Disk Space

When planning your SQL Server Hardware Requirements it is important to remember that database applications can extremely Input/Output intensive.

Most senior SQL Server DBA’s would recommend using fast SCSI drives and quality disk controllers (or if you have no budgetary restrictions a SAN environment).

As an important note when using write caching disk controllers, I recommend that you confirm with the manufacturer before implementation that they are suitable for use with Database Servers.

Using inappropriate write caching disk controllers can result in data loss if a "catastrophic failure" occurs, as an example: loss of power.

If you want redundancy and fault tolerance you should consider using RAID. To quote from Microsoft "The different Levels of RAID provide varying levels of performance and fault tolerance. Hardware based RAIDS provides more performance that Operating System RAID".

Some of the characteristics of RAID can be seen in the table below:

RAID level	Description	Characteristics
RAID 0	Disk Striping/ No Parity	Excellent performance – Negative fault tolerance
RAID 1	Disk Mirroring/duplexing	Read and write performance is good and fault tolerance is excellent
RAID 5	Disk Striping with parity	Read performance is excellent. Write performance is moderate - Fault tolerance is excellent
RAID 10	Disk Mirroring combined with disk striping (RAID 1 + 0 )	Excellent read performance Excellent write performance Fault tolerance is excellent BUT can be expensive due to the number of disk required.

Memory

An insufficient amount of RAM can cause your SQL server to continually read data from disk instead of cached memory.

This will impact on query performance in most cases this impact will be significant. Having an appropriate amount of memory will allow SQL Server to process your queries more efficiently: it can hold more data in its cache.

Conclusion

In conclusion there are a number of factors that can have influence on your SQL Server Hardware Requirements and it is important to remember that the above specification server is very likely to perform badly.

I have yet to hear of a SQL Server that has been "over specified" in terms of hardware technology performing poorly – at least not as a result of the hardware.

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