What should I do if I have a machine with six or eight databases all on one machine (say in a Web application hosting...
type of scenario). Do I need to have a separate physical hard drive for each database on the machine?
In practice with the server cost in mind, my recommendation would be to group the databases on a RAID array and the transaction logs on a separate RAID array. Properly configured hardware is a core component for SQL Server performance and based on the criticality; stay tuned for additional tips relative to hardware configurations.
MEMBER FEEDBACK TO THIS ASK THE EXPERT Q&A:
I agree with the premise that in the real world you are not going to have enough physical drives or RAID adapters to provided separate physical arrays for each database. But Jeremy doesn't justify his advice here. I'd like to understand his logic. Why this approach and not just lump everything into one large array? Or, if one of the databases is doing significantly more insert/update/deletes than the others, maybe you'd see better performance by isolating the transaction log of that one database on its own array, and lumping everything else together on the other array.
Thank you for the questions. As far as configuring the hardware is concerned, from a high performance perspective, it is important to split the different types of SQL Server processing (random, sequential, etc.) onto different drives. This enables the various types of I/O to be split across as many drives as possible. With a single RAID 5 set the I/O will all be contending for the same resources and cause disk queuing.
Regarding isolating the transaction log of one database on its own array, and lumping everything else together on the other array -- that could definitely be the case based on unique business needs. From a processing perspective, it is still important to split the database from the transaction logs.
Thank you again for the questions and I hope this clarifies the additional items.
Jeremy Kadlec, Performance and tuning expert
Do you have comments on this Ask the Expert Q&A? Let us know.
Dig Deeper on Microsoft SQL Server Performance Monitoring and Tuning
Related Q&A from Jeremy Kadlec
Adding non-clustered indexes to SQL Server columns and tables frequently queried is possible. Learn how to add non-clustered indexes to SQL Server ...continue reading
Learn how to view a query execution plan in SQL Server with SQL Server Management Studio or Query Analyzer. Review and decrease query plan sub tree ...continue reading
Want to change the collation to SQL Server 2005 standards after upgrading databases from SQL Server 2000? Learn the best approach involving DTS and ...continue reading
Have a question for an expert?
Please add a title for your question
Get answers from a TechTarget expert on whatever's puzzling you.