In reply to Martin.

It’s not “additional [cpu] load”, it’s actually less. Deferred OTF image generation means you’re only generating thumbnails one at a time, not a dozen at a time which means a shorter cpu usage spike affecting other processes. And, only generating the thumbnails that are actually needed means a net of less cpu usage as well.

There are important concerns with what happens in that approach with failures and retires, but those are not really any different than the concerns voiced by Ozz with failures with the current approach. One wouldn’t just keep retrying generating a thumb repeatedly, it’d quickly give up, ideally with error logging available to a lay user that the current approach doesn’t have.

While file storage is somewhat cheap, it’s not always cheap. It’s why we do often end up offloading storage on large sites to things like S3, at scale storage costs do add up. Case and point just had to upgrade a site on Nexcess from $100/m to $250/m solely due to ticking over the 100GB mark.

Finally, dealing with large numbers of files also has a performance impact. You don’t see that at 10-20,000 files in a directory, but you do at 100,000 in a directory. Simply doubling the number of thumbnails on disk will impact impact performance on large sites.