One year ago Akamai rolled out warm migrations to the Linode platform for both data center and host migrations, and resizing operations. During a traditional cold migration, the target Linode is shut down, its data copied to a new host, and the new Linode booted. A warm migration differs from a traditional cold migration in that the target Linode continues running until the Linode is synced to a new host. At that point, the Linode powers down, and because the local NVMe data is mirrored one-to-one on the new host, the new Linode boots exactly the same as it would a reboot on the previous host. If a resize is necessary, the resize can happen on the new host while the Linode is powered down and immediately booted back up.
We pioneered this new technology for two reasons, both crucial to combatting customer downtime, or the time a Linode is occupying space but is powered down. The first reason is that cold resizes (previously known as resizes) required the Linode to stay powered down for the duration of the migration; the resize would take place on the destination host, and then the new Linode would boot on the new host. A migration is needed for resizes because the current Linode’s host is not guaranteed to have space if the Linode is sized up, and if the Linode is sized down, better hardware on a new host might be available. For larger Linodes, this required anywhere between a few minutes to hours of downtime. The goal was to drastically shorten this timeframe. The second reason we developed warm migrations is that Live Migrations can only operate between compatible CPU types. A warm migration doesn’t have this restriction.
Customers started warm-migrating last year, and we’re proud to be able to share just how much downtime we actually saved. In a year, customers warm-migrated 11.6 Petabytes of data across over 58,000 Linodes, saving a total of more than 6,100 hours of downtime. Again, this downtime is the time that the Linodes were processing requests, serving customers, supporting business, and doing everything else an Akamai user needs, instead of being powered down, while still able to resize and migrate to new destinations.
| Data Migrated | 11.6 | Petabytes |
| Migrations | 58,000 | Linodes |
| Downtime saved | 6,100 | Hours |
It took an outsized effort to bring Warm Migrations to life, but we constantly strive to meaningfully improve the experience customers have on our platform. Multiple teams across the company worked together with a unified vision to see this project through to the end, and from an engineer’s standpoint it’s very rewarding to see this large impact. If you’d like to try warm migrations out, the feature is available as a resize option on the Cloud Manager. And, if working on large, impactful projects like this interests you, we’re hiring.
Tags
