It is not possible to increase the disk space of the build container permanently.
This is required once you have more than 20 locales to be built while static content generation while the cloud deployment process, and on transfer step you will face errors like these:
gzip: /app/pub/static/adminhtml/vendor/backend/fr_CH/jquery/ui-modules/resizable.js.gz: No space left on device
This is caused due to the too low size of the build container (8Gb).
The temporary solution from Magento Cloud engineers was to adjust cloud configs (cloud support has access there only) for increasing space from 8Gb to 16Gb. However, quote:
this will likely be downgraded back to 8GB at some point.
, because these configs are placed under a version control system and these changes are just left there as modifications. So can be rest to default state once the new version of configs/codebase of cloud configs will come in.
Please add the possibility to change the build container disk space permanently.