Linux: Large int array: mmap vs seek file?

Question

Suppose I have a dataset that is an array of 1e12 32-bit ints (4 TB) stored in a file on a 4TB HDD ext4 filesystem..

Consider that the data is most likely random (or at

Answer 1

Seek performance highly depends on your file system implementation. Ext4 should be a good choice as it uses extent trees. Also if your file has linear contiguous allocation the extent tree will consist of a single entry, which makes seek trivially efficient.