Moving data has become common practice for various reasons. You might be upgrading your hardware, moving to a new data centre for the cloud, creating a test database, merging departments or authorities, or trying to cut costs by moving older files to a less expensive option. Whatever the reason, making sure it all goes swimmingly is not easy.

Many storage environments are complex, with ‘hot’ data you need to access frequently and ‘cold’ data you’re only keeping hold of for legal requirements. The applications and processes involved, let alone the disks, tapes, routers and switches used, mean that serious planning is required to ensure any migration, no matter how big or small, is a success.

Discovery   

It’s important to carry out a discovery of the existing environment so you understand all the relationships, both human and technological, and can then map out how they will translate into the new environment.  There might be storage appliances you’re not aware of or a specific order in which applications and databases need to boot. Understanding the pathways between your hosts and the arrays they use and how they might change on migration will give you an overview of any potential issues that might crop up, as will highlighting the levels of responsibility within your IT teams and the participating departments. 

Timing

Storage migration can have a significant impact on your system performance. This is where knowledge of the capacity of your SAN, the patch levels and the network loads you routinely carry is vital. Overloading a network with storage traffic can reduce availability not only of the data being moved but also of all the data on your network. Therefore the acceptable level of impact, the amount of bandwidth being offered and the time of the day at which the migration takes place needs to be agreed with all stakeholders. Where possible migrations should be done outside normal business hours and there should be general agreement about what is acceptable downtime.

Virtual v physical

The prospect of migrating live virtual machines (VMs) as well as physical servers can be scary. There are tools to help. VMware’s VMotion for instance ensures the VMs can access the resources they need during a live migration. Ask questions of the vendors you are working with to make sure the tools you are using don’t require changes you are not aware of.

Security

During migration data must not be left vulnerable. Permissions and security can get lost leaving data exposed. The choice here will be between block-level or file-level migration. Block-level migration can affect your thin provisioning, while file-level can leave data more vulnerable because of the wider information it exposes. A deep dive into what information is being copied and the vendors’ capabilities means the best decision can be made on the type of data migration to be used, although Microsoft Active Directory for instance is able to maintain security settings during a file-based migration.      

Preparation

Successful migration is all about pre-planning. By understanding your data and the inherent risks to its transfer from one environment to another before you go ahead, as well as the business case for it actually going ahead, is the best approach. What are you hoping to achieve and what do you want to avoid happening are the questions you should be asking of yourself, your organisation and the teams you’ll be working with. 

A failed migration can put a brake on vital business processes and can damage your customer-facing operations. With good in-depth, preparation you can make data migration successful. 

iomart’s public cloud consultancy SystemsUp has worked with public sector organisations to facilitate successful storage migrations. Find out how they helped an NHS Community Support Unit plan and manage a SAN storage migration. Click here.