"Suppose you’re going from a single database to a service that hides the details of a new storage solution. Have the service wrap around the legacy storage, and ramp up writes to it slowly. With backfilling, comparison checks on read (another feature flag), and then slow ramp up of reads (yet another flag), you will have much more confidence and fewer disasters."
Does the author mean to say:
"Have the service wrap around the legacy storage, and ramp up writes to the new system slowly"? It reads like he's saying ramping up writes to the legacy system.
Also I am confused by his use of the word "backfilling", what would being backfilled? IOPS to the new system after IOPs to the legacy system? Is that the idea.
This was a good read. Kudos to the author to putting it out there.