SQL Server Tips by Robin Schumacher

Coming Physical I/O Crisis?

A number of database experts are predicting a coming crisis with respect to database performance and disk I/O. This prediction has to do with the fact that hard disks are continually increasing in their ability to handle more storage capacity. The concern is that the I/O’s per second (iops) that these disks can service has not kept pace with their ability to handle more space.

For example, a DBA used to have ten or more disks at their disposal to service the storage needs of a 500 GB database. But now, storage vendors can offer IT managers the ability to store the same amount of data on only two disks. Such a proposal is not only attractive to IT management, but it often appeals to system administrators as well because fewer disks normally mean less work and maintenance.

Such a situation can place a stranglehold on the DBA’s database because the number of iops that such a disk configuration can handle is far below the iops capability of the previous ten disks.

Storage is typically priced by capacity and not by iops, so database gurus are sounding the alarm for all DBAs to hear; make sure their voice is heard when the storage configuration of the database server is being decided. If their opinions are not heard, the database may be robbed of performance because of poor disk purchasing decisions.

The above book excerpt is from:

High-Performance SQL Server DBA
Tuning & Optimization Secrets

ISBN: 0-9761573-6-5
Robin Schumacher

 http://www.rampant-books.com/book_2005_2_sql_server_dba.htm