Whenever live restore reads data from a source file it will copy that data into the destination file (otherwise know as read promotion).

In our PoC we do this for all reads from a source file, but there are cases where it may be redundant. For example if we read a page and immediately write it back to disk.

Once we have performance tests up and running we should review this behaviour. Specifically:

• Are there cases where we should read from the source file but not perform read promotion?
• How much of a performance increase do we get from this change?
• How complex is the new solution, and is the perf gain worth the increased maintenance cost?