Hint: noatime and relatime in fstab

Atime updates turn reads into metadata writes. Database data directories rarely need atime.

Options

/dev/mapper/vg-data  /var/lib/mysql  ext4  defaults,noatime  0  2

noatime disables atime updates.

Modern kernels default to relatime (update atime only when older than mtime/ctime or past a threshold). Document intent:

defaults,relatime,nodiratime

Verify

findmnt /var/lib/mysql
grep mysql /proc/mounts

NFS

Attribute traffic on NFS is a separate cost. Prefer local/block volumes for InnoDB tablespaces. Measure before putting data files on NFS.

Small mount change. Removes a class of self-inflicted latency before you touch InnoDB tunables.