To disable access time updates (noatime) for the /var directory in Linux, you will need to edit the /etc/fstab file.
The /etc/fstab file specifies the available disk partitions and the options used to mount them. To disable access time updates for the /var directory, you will need to add the noatime option to the mount options for the /var partition.
For example, if the /var partition is mounted on /dev/sda1, you can edit the /etc/fstab file to add the noatime option as follows:
/dev/sda1 /var ext4 defaults,noatime 0 2
This will disable access time updates for the /var partition.
Note that the noatime option disables access time updates for all files and directories in the /var partition. This can improve the performance of the system by reducing the number of writes to the disk. However, it can also prevent certain applications from functioning correctly if they rely on access time updates.
You should be careful when modifying the /etc/fstab file, as incorrect entries can prevent the system from booting. Make sure to test the changes to the /etc/fstab file before rebooting the system.