Metrics are:
process_io_read_bytes_total - the number of bytes read via io syscalls such as read and pread
process_io_written_bytes_total - the number of bytes written via io syscalls such as write and pwrite
process_io_read_syscalls_total - the number of read syscalls such as read and pread
process_io_write_syscalls_total - the number of write syscalls such as write and pwrite
process_io_storage_read_bytes_total - the number of bytes read from storage layer
process_io_storage_written_bytes_total - the number of bytes written to storage layer