how to fix the zero sub-second timestamp issue

[Gilbert]

I use snapraid status and found there are 81 files with a zero sub-second timestamp issue, and run 'snapraid touch' to fix. the reuslt is nothing changed and the error still there. There is no problem to sync and access these files, any comments?

[Gilbert]

btw, i checked the access to the files is properly granted.

[Bill McClain]

Did you sync after the touch?

The sub-second timestamp is an optimization feature to help identifying moved or copied files. Your files are protected even without it.

From the manual:

This improves the SnapRAID capability to recognize moved and copied files as it makes the time-stamp almost unique, removing possible duplicates.

More specifically, if the sub-second time-stamp is not zero, a moved or copied file is identified as such if it matches the name, size and time-stamp. If instead the sub-second time-stamp is zero, it's considered a copy only if it matches the full path, size and time-stamp.

[Rysz]

This also depends on if your filesystem supports sub-second timestamps.
https://stackoverflow.com/questions/14392975/timestamp-accuracy-on-ext4-sub-millsecond

Ext4 only supports nanosecond timestamps if the inodes are 256 bytes or larger.
The default inode size of mkfs.ext4 depends on your distro. Some "low-power systems" distros still use 128 bytes to save disk space. And some other distributions also have the rule that "if the partition is smaller than 512 MiB, use 128 byte inodes".