The OS doesn't write bytes to the storage; it writes blocks. For modern drives the sector size is 4k, and the block io size is likely to be 4k unless utilizing 512b emulation.
So, the OS will always send 4k minimum writes to the storage device. In this case updating just the 8bytes would still result in a 4k write; at least to the wal then again to update the page plus index updates and etc.
The OS doesn't write bytes to the storage; it writes blocks. For modern drives the sector size is 4k, and the block io size is likely to be 4k unless utilizing 512b emulation.
So, the OS will always send 4k minimum writes to the storage device. In this case updating just the 8bytes would still result in a 4k write; at least to the wal then again to update the page plus index updates and etc.