Maynard Handley wrote:
> Of course building is a different type of task from a standard
> file system! In particular building generates
> a large number of blobs which are essentially ephemeral and do not need the strong promises of persistence
> provided by the file system.

Andrey replied:
> Yes they do need certain guarantees. Including persistence and integrity. You need the
> intermediate files to be able to perform incremental builds. You need to be sure they
> are not corrupted e.g. due to the underlying media failure when you (re)use them.

It could be argued that the intermediate files don't need strong promises of persistence: if the system goes down and they don't reach disk, that really isn't a problem. All you need is a promise that they either don't exist, or exist in a coherent state, which is a much cheaper promise to fulfill (you don't need to flush anything).

Apart from that, it sounds like people are proposing writing a new special-purpose database engine purely for the purposes of storing and compiling source code. It would be fascinating to see if this does actually result in significant performance improvements over modern Linux, but the investment in time would be considerable, and no-one has even addressed the cost/benefit ratio.

In the meantime, a build system that exists is superior to one that does not.