The docs for Archive::Tar::Wrapper state that the module "never stores anything in memory, but works on temporary directory structures on disk instead" so perhaps that is what you need.

You also said:

Currently we only have 2GB within the Virtual Server ... Simply upgrading the systems memory is unfortunatelly not an option.

which is rather odd. Ordinarily the use of a VM means that upgrading the system's memory is a doddle. Perhaps you have been misinformed?