Short answer: a few weeks to a few months for relatively simple websites and as much as a year for highly complex websites.
From a cost perspective, the level of team effort ranges from a few hundred hours (tens of thousands of dollars) to a few thousand hours (hundreds of thousands of dollars).
Regardless of the size, scale, and scope of a website, there are three activities that need to performed:
- Create or replicate the front-end UI/UX
- Create or replicate the back-end functionality
- Migrate the content, data, and metadata
In order to do this, there are some things you need to do to prepare, such as inventorying the content and modules. If your functionality is complex, it would be important to create a test plan, which would involve identifying and inventorying all of the important user stories, use cases, and user requirements so these can be tested prior to relaunch.
In addition, if the organization has invested any amount of time in search engine optimization (SEO) or accessibility (Section 508 / WCAG compliance) then there needs to be some mapping, inventorying, and identification of the before snapshot so the after snapshot can be compared, resolved, and/or refactored to ensure that you did not accidentally introduce regression errors.
The more complex the legacy website, the more time and attention to detail will be required to replace and migrate an existing website into Drupal 8 (or 9).
So, there will be some prep work that needs to be done in advance, the actual work of migrating and upgrading the website, and then testing and refactoring after migration. Assuming that this is primarily a migration, as opposed to a redesign and redevelopment with significant enhancements to the UX, a typical team would include, at a minimum, these roles:
- Scrum master, project manager, team leader
- Business analyst, quality assurance engineer
- Front-end developer
- Back-end developer
Not everybody might be required full-time for the duration of the project but, depending on the site, you may need multiple people filling the same role. Some of the work must be done sequentially while other work could be done in parallel.
For more detailed information, please see our Agile Guide to Migrating Out of Drupal 7.
Agileana is a Washington, DC based team with over a dozen Acquia Certifications in Drupal 7 and D8. We serve primarily government agencies, nonprofit organizations, member associations, and higher education.