Service Now Instance Migration Projects

Introduction

Service Now Instance Migration Projects are similar in many ways to any other migration project. However, Precision Bridge has some specific functionality to assist with the fast development of these projects.

Often the vast majority of mappings will be 'simple' mappings, however reference and list fields may need special consideration since the id's of configuration data on the source/target may be different, particularly if you are merging two instances together.

Reference Fields

It is important to identify all reference fields in your data where the id of the source and target referenced record may be different. 

Precision Bridge strongly recommends making use of Precision Bridge or Update Sets to migrate configuration and system data between servers since this will maintain the sys_id and make mapping the fields that reference these much easier to manage.

One consideration is users and groups. Often, these are populated from an external system using LDAP (or similar) Using this methodology to populate users and groups on your target server will not maintain the sys_id's of records and make mapping user/group referencing fields harder. It is therefore recommended that you use Precision Bridge to migrate Users/groups where at all possible, particularly if the target server is greenfield.

Quickly Build Mappings using the Form Mapping Generation Wizard

Although Precision Bridge does provide templates for most areas of instance migration, it is sometimes easier to start with an empty project and add the form mappings for the tables you want to include using the Form Mapping Generation Wizard. This is particularly true for CMDB, where there are likely to be many customisations and additional CMDB class tables that will need to be added.

If you do choose to use a template, the Form Mapping Generation Wizard can be used to extend it.

To run the form mapping generation wizard  from the design view of an open project, go to Project -> Generate -> Generate Form Mappings

More information on the wizard can be found in this article: Generate Form Mappings for Service Now Instance Migration

Additional Mapping Types to Handle Lists and Values with Embedded References

While reference mappings can be used to map reference fields, Lists are stored as a set of references and a reference mapping will not work. Precision Bridge has a mapping type ID List that is only available for instance migration projects and is designed to handle transforming the list of source id's into a list of target ids using key mapping correlation. More information can be found in this article: Creating an ID List Field Mapping 

Some fields can contain embedded references (such as conditions) and some can contain either a value or a reference (such as variable values) The ID Replacement Mapping can often handle these, and it is worth understanding how it works. More information can be found here: Creating an ID Replacement Field Mapping