If ext4 need no defragmentation then how/what definitively to optimize its disk access operation
Nothing ext4 specific IIRC. There are some kernel optimization you can do, like this, but consider some of that to be a placebo:
https://unix.stackexchange.com/questions/30286/can-i-configu...
Other than that, maybe consider an alternative filesystem like f2fs or xfs depending on the medium.
Nothing ext4 specific IIRC. There are some kernel optimization you can do, like this, but consider some of that to be a placebo:
https://unix.stackexchange.com/questions/30286/can-i-configu...
Other than that, maybe consider an alternative filesystem like f2fs or xfs depending on the medium.