This is the latest posting on rsync - I have a few comments
I am testing just using the USB backup app ( that just got updates since the original OS5 update )
The commands are not working like the older version
I am hoping someone that has looked at the source can tell what changed.
I am looking into why the copy is replacing large 100GB+ Acronis backup files when NOTHING is changed on the NAS ( you can see it moving over a extra file with a random file extension then replacing the old file
I am using copy as it is the closest to the old Mirror backup command.
this link may help on other rsync items
here is what I thing may be different
- USB disk format
–modify-window
When comparing two timestamps, rsync treats the timestamps as being equal if they differ by no more than the modify-window value. This is normally 0 (for an exact match), but you may find it useful to set this to a larger value in some situations. In particular, when transferring to or from an MS Windows FAT filesystem (which represents times with a 2-second resolution), --modify-window=1 is useful (allowing times to differ by up to 1 second).
So using any of the FAT/ EXFAT formatting on a external backup disk may not work well
( most suggest Unix or basic windows only )
rsync finds files that need to be transferred using a “quick check” algorithm (by default) that looks for files that have changed in size or in last-modified time. Any changes in the other preserved attributes (as requested by options) are made on the destination file directly when the quick check indicates that the file’s data does not need to be updated.
– one option is checksum —
-c, --checksum
This changes the way rsync checks if the files have been changed and are in need of a transfer. Without this option, rsync uses a “quick check” that (by default) checks if each file’s size and time of last modification match between the sender and receiver. This option changes this to compare a 128-bit checksum for each file that has a matching size. Generating the checksums means that both sides will expend a lot of disk I/O reading all the data in the files in the transfer (and this is prior to any reading that will be done to transfer changed files), so this can slow things down significantly.
Just suggesting we ask a few of our regular poster if they know from the backup source code how the command options have changes.
