Which utility is used to change filesystem check frequency on an ext2 filesystem without data loss?

The utility used to change filesystem check frequency on an ext2 filesystem without data loss is tune2fs. This command allows you to adjust various tunable filesystem parameters, which include the maximum mount count and the interval between filesystem checks.

Specifically, tune2fs provides options to set how often the filesystem should be checked based on the number of mounts or time. This is important for maintaining filesystem integrity and ensuring that any potential issues are detected in a timely manner. By adjusting these parameters, you can customize the maintenance behavior of your ext2 filesystem according to your needs, all while avoiding any data loss.

Other utilities mentioned, such as fsck and e2fsck, are used primarily for checking and repairing filesystems rather than adjusting their parameters. fstrim is associated with managing disk space and is mainly used in SSDs to inform the device which blocks of data are no longer in use. Therefore, tune2fs is the correct choice for achieving the task of changing the filesystem check frequency without risking data loss.