Random "Date Modified" Flag Errors on Writes to WD (Using Robocopy) [NTFS?]

Meloman · October 15, 2015, 1:33am

Robocopy finds a number of mismatch between source local USB NTFS Drive and WD World Edition II while the “Date Modified” tag from a Windows stand point appears exactly the same on both source and destination.

Windows says 07/11/2009 5:01 PM for both the corresponding USB Drive and WD Drive files.

Robocopy log says “Newer” and state date as 2009/11/07 21:01:06

NOTE that NOT ALL FILES behave like this ! Only maybe 1 out of 4 files (at random). And it only behaves like this during writes to WD. If I read from WD there is no issue…

From what I have read elsewhere in the forum this could have something to do with the format of WD not being NTFS… Then what is it ? and how can I solve this issue ? I have 12 000 music files that I need to sync on a regular basis. So I cannot afford to copy over identical files all the time.

Thank you !

Trancer · October 15, 2015, 3:00am

The File System for the Western Digital My Book World Edition, as well as the WD ShareSpace and the WD My Book Live, is the Linux-based EXT3 File System. It can not be changed to any other File System.

Perhaps it would be best to investigate the proper use of Robocopy on EXT3 and/or Linux Systems.

Regards,

Meloman · October 15, 2015, 3:00am

Thank you ! This is very useful information.

“The standard ext2/ext3 inode has 3 time fields, last inode change, last file data change and deletion time. These timestamp fields have a resolution of 1 second. The only time field that maps from NTFS to ext2/ext3 is the file data modification time.”

The NTFS timestamp is more precise than the resolution for the EXT2 / EXT3 inode file systems. Therefore, a different option has to be tweaked with ROBOCOPY to allow for a less precise timestamp measurement.

Fortunately, out of the box there is a /FFT switch for ROBOCOPY which specifically accomplishes this task by assuming FAT File Times which translates to a more forgiving 2-second granularity. This is more than sufficient to account for the one-second granularity that the EXT2 / EXT3 file systems support.

Note, it would be appreciated if WD specified the Drive Format and lack of option to change it. (I have seen more quetions related to file system) I hope this post can help other with this kind of issue.