4 ms·

Can I have a reference for that hardcoded buffer size please?

• macdice 6y ago
  See man pages for mkfs.xfs, mkfs.ext4. On other Unix systems block size is/was more variable, but on Linux you can't exceed the 4kB memory page size. So it is not possible to match database block size (typically 16kB for InnoDB, 8kB for PostgreSQL). (Exception being ZFS which has a completely different architecture and can do atomic writes.) Note that I am not saying buffered IO would necessarily be atomic at that level on (say) ancestral SGI XFS or FreeBSD UFS with block size matching the database's (I don't know if it might it some circumstances split writes on sector boundaries for some reason)! Just that it's already a non starter when the block size is too small.