Before listing the specifics of what data migration entails, let us first define it in the context of data storage. Data migration is a one-time activity that is undertaken for a specific purpose. The purpose can vary from organization to organization, but it must justify the need to undertake the endeavor in the first place. Because any time you migrate data there is an element of risk to the business, if you find yourself migrating the same data all the time, you have other issues in the environment that warrant examination.
The second important point in any migration is that the type of data you are migrating influences what migration method you select. For example, if your database is being migrated using simple copy tools available to any user, and it is not shut down during the process, whatever you have copied may not be usable. The method must align with the data you are migrating.
What is a successful data migration? The ultimate goal is to get the job done with minimum impact to your environment.
Plan for success. A data migration exercise, no matter how small it is, can have undesired consequences if not planned properly. No IT manager likes surprises, least of all being up at night worrying about data loss or unexpected downtime because of poor planning. Don't cut corners - get a project manager involved . If your company does not have a project manager who is familiar data migration processes, look at bringing in a resource. Project managers with data migration expertise are out there. A project management expert should create a detailed project plan that includes tasks, subtasks timelines, roles, responsibilities and dependencies. All the parties involved should have an opportunity to voice their concerns (in a controlled manner) and key requirements are factored in while building the plan. A critical component of the project plan is also a well-planned test and back-out plan.
Get the experts. While moving data may sound like any other IT project that can be handled internally, the reality is, it is not. This is especially true if the migration involves moving data from one physical resource to another or when you are moving it from one geographical location to another (i.e., a data center migration). Bringing in outsourced experts does not mean they replace the value that your internal resources bring to the table. Bringing in an outside resource that specializes in that technology allows your staff to focus on the day-to-day operational activities while the added, dedicated resource focuses on the details around the migration itself.
Know your objectives. This may sound repetitive, but before you embark on a data migration project, you must be clear about the reasons you are crossing that bridge. Is it technical or purely financial? How much money do I have to spend on this project? What cost savings will the migration effort bring about? What sort of impact does the business experience when I do the migration? How much downtime can the business tolerate? Have I evaluated all my options before making the decision? A detailed analysis of all the reasons for the data migration, and their impact on the business, will drive you to the set of objectives to be applied to planning the process. Do not start looking at the technical options before you have completed this exercise. Do not even engage any third-party organization before you are clear about what the objectives are and what they will help you accomplish in the short, medium and long term.
Know your options. There are many different ways to migrate data. There is no such thing as the right way or the wrong way. The method selected depends entirely on your requirements, such as downtime, resource availability and the amount of data you're migrating. You don't need to know every method in minute detail, but knowing the options will help you make an informed decision about how best to accomplish your objectives. If you are bringing in an outside resource to help you make the decision, keep in mind that while they may bring a fresh perspective, that resource may also prefer certain migration techniques if they are aligned with a storage vendor. In such cases, vendor-independent organizations may be the best suited to provide an unbiased analysis of your environment and the methods that are most appropriate to migrate your data. Also, keep in mind that there is no such thing as a one-size-fits-all data migration technique for all data types. The one-size-fits-all approach has its advantages and disadvantages. Among the advantages is the ability to use the same consistent migration process across all platforms and applications. The disadvantages are the lack of flexibility to downtime and lack of customization. This approach may be best suited for large-scale migration efforts such as a data center move or an array-to-array migration, whereas other customized approaches will be preferred for small migrations, such as an application or database migration for a very specific purpose (like a server upgrade or platform migration).