[ayende]

Writing on a page (4KB / 8KB) boundary is almost always a good idea. Because there is an overhead per page that you have to account for. It can be in the range of 16 - 64 bytes, so having a 256 mini page is probably a bad idea.

Most of the _data_ is also not going to fit in 256 bytes anyway.

[lichtenberger]

It might add some overhead, but I guess it depends on the page implementation, but 16 bytes seems to be the minimum (and Optane Memory might , I agree. That said if someone changes only one record the best thing is to write in the smallest granularity possible on the storage medium.

So, it might well be that someone is only interested in only one or a few records. Why then fetch and cache a whole 4Kb page if latency is good in both cases (4kb and 256 bytes)? On the other hand I agree that you should probably cache more data from a hot page.