Database Migrations the VxVM Way

Rainer Raab

The duties of a Unix systems administrator range from the simple and mundane, to the complex and mission-critical. We are often called upon to reset a password, remove an unwanted file, restore a backup, apply security patches, etc. Though not very challenging, these tasks are important and must be performed with vigor. Less frequently, we are enlisted to perform a challenging task, offering us a chance to learn something new and prove our worth. Such tasks include operating system upgrades, building Web server farms, allocating new disk arrays, and database migrations, to name a few. Database migrations, which are the most complex and mission critical, offer the most reward and the opportunity to add new skills to one's oeuvre.

Migration Methods

The term database migration can mean a variety of things. It can refer to the movement from one database to another where the data is moved between the databases, such as moving from an Informix IDS version 7.31 to a new IDS version 9.40 database using Informix dbexport/dbimport utilities. Or, it can refer to the movement of the database to an entirely new platform, such as moving from Solaris 2.6 on SPARC to Linux 2.6 or Windows Server 2003 on Intel x86. It can refer to the movement of the database from one server to another, such as moving from a Sun Enterprise E450 to a Sun Fire 4800 system. Or, it can simply mean moving the database from one disk array to another.

The operative word here is "move". An in-place upgrade of a database, from one version to another, is not considered a database migration. For example, upgrading an Informix IDS version 7.31 to IDS version 9.30 would not be considered a database migration.