Background
I use rsync/cygwin on Windows 10 to backup all my local files (source) to an external hard drive (destination). I used this guide http://www.howtogeek.com/175008/the-non-beginners-guide-to-syncing-data-with-rsync/ as a tutorial on how to use rsync/cygwin for backing up. Note: My external hard drive is formatted to NTFS.
On the very first backup, I manually copied/pasted the desired folders to the destination. All subsequent backups are done using rsync as described below.
My backup method using rsync/cygwin
On Windows, I created a backup.bat file with my rsync commands so I can can quickly plug in my external drive and start the backup. Below is an example of my backup.bat file, where C is my local drive, and E is my external drive.
pause
rsync -avhP --delete --log-file="/cygdrive/C/Users/MyUsername/rsync-backup-log.txt" "/cygdrive/C/Users/MyUsername/Folder A" "/cygdrive/E/Backup/"
rsync -avhP --delete --log-file="/cygdrive/C/Users/MyUsername/rsync-backup-log.txt" "/cygdrive/C/Users/MyUsername/Folder B" "/cygdrive/E/Backup/"
rsync -avhP --delete --log-file="/cygdrive/C/Users/MyUsername/rsync-backup-log.txt" "/cygdrive/C/Users/MyUsername/Folder C" "/cygdrive/E/Backup/"
pause
To ensure I don't have permission issues, I edited my C:\cygwin64\etc\fstab file to below:
none /cygdrive cygdrive binary,posix=0,user,noacl 0 0
Problem/issue
The issue I am having is that I often see "Permission denied (13)" errors. Below is an extract of the rsync log. Notice how some files/folder are backed up without errors. However, there are some files/folders that give permission errors.
...
2016/12/17 15:57:04 [2968] >f+++++++++ Documents/Subfolder A/IMG_5678.JPG
2016/12/17 15:57:04 [2968] >f+++++++++ Documents/Subfolder A/IMG_5679.JPG
2016/12/17 15:57:04 [2968] >f+++++++++ Documents/Subfolder A/IMG_5680.JPG
2016/12/17 15:57:04 [2968] >f+++++++++ Documents/Subfolder A/IMG_5681.JPG
2016/12/17 15:57:04 [2968] >f+++++++++ Documents/Subfolder A/IMG_5682.JPG
2016/12/17 15:57:04 [2968] >f+++++++++ Documents/Subfolder A/IMG_5996.JPG
...
2016/12/17 15:58:03 [6052] >f+++++++++ Folder B/Subfolder C/FileD.docx
2016/12/17 15:58:03 [6052] cd+++++++++ Folder B/Subfolder C/Subfolder E/
2016/12/17 15:58:04 [6052] >f+++++++++ Folder B/Subfolder F/FileG.docx
2016/12/17 15:58:04 [6052] rsync: mkstemp "/cygdrive/E/Backup/Folder B/Subfolder C/.FileD.docx.dBBzQZ" failed: Permission denied (13)
2016/12/17 15:58:07 [6052] rsync: mkstemp "/cygdrive/E/Backup/Folder B/Subfolder F/.FileG.docx.8DkCUR" failed: Permission denied (13)
2016/12/17 15:58:07 [6052] rsync: recv_generator: mkdir "/cygdrive/E/Backup/Folder B/Subfolder H/Subfolder J" failed: Permission denied (13)
2016/12/17 15:58:07 [6052] *** Skipping any contents from this failed directory ***
2016/12/17 15:58:07 [6052] >f+++++++++ Folder B/Subfolder H/FileK.xlsx
2016/12/17 15:58:07 [6052] cd+++++++++ Folder B/Subfolder H/Subfolder J/
2016/12/17 15:58:07 [6052] rsync: mkstemp "/cygdrive/E/Backup/Folder B/Subfolder H/.FileK.xlsx.WQa396" failed: Permission denied (13)
2016/12/17 15:58:07 [6052] sent 91.52M bytes received 1.79K bytes 9.63M bytes/sec
...
Troubleshooting
To troubleshoot, I navigated to one of the folders with the permission error in Windows Explorer (on the external hard drive). Below is a screenshot of the dialog notification I get. When I click Continue to gain permission, the folder opens, but its empty. When I re-run rsync command (backup.bat), the files in that folder are properly backed up without error.
Screenshot:
rsync: send_files failed to open "/cygdrive/...": Permission denied (13)
. So send_files not mkstemp. Problem on the Windows side. So different situation, but for posterity, my solution was to right-click cmd.exe and Run as administrator.