Double caching when using cache-after-prepare

[daviesrob]

Currently, the original VM image is cached, even when cache-after-prepare is in use. This results in two copies being cached when the prepared version is saved later, which can result in unwanted evictions, especially for the bigger VMs (e.g. Solaris).

Would it be possible to stop the original VM from being cached? The disable-cache switch currently turns off both; it would be useful to be able to disable caching of the pre-prepare version independently.

[neilpang]

this is by design.
if the original image is not used, it will be dropped later. and only cache after prepere image will stay in the cache.

This is for the cases that : there are multiple workflows with the same base image, but different prepare.

[daviesrob]

I guess it might sort itself out in the end. The problem is that two copies of the Solaris VM are big enough to start evicting most of the other images. Where I don't want to prepare images in different ways, it would be useful to be able to ensure only one of them gets stored.