USB Copy size missmatch

Discuss backup and restore functions of the DiskStation with respect other DiskStations, USB/eSATA, network backup, or other rsync clients.
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Posts: 1
Joined: Sat Jan 13, 2018 12:43 am

USB Copy size missmatch

Unread post by Xarin » Sat Jan 13, 2018 1:04 am

Doing a big backup before restructuring my storage and noticed that usb copy doesn't seem to be copying all of the data although it finishes without errors. Wondering if anyone else encountered this and what might cause it. As far as I know I don't have any symlinks or anything like that there.

Quick update: ssh'ed into the synology and did a diff of both directory's. Looks like there were certain files that it just skipped with no indication why, It could be that they had filenames with less typical characters, there weren't any permissions issues, and doing a standard copy/paste (skip) added the missing files without much issue.

kinda disappointed with synology on this one. USB Copy has some nice triggers to backup data when a device is plugged in but it looks like the backups can't be guaranteed to be complete as well as the issue with trying to backup multiple locations to the same usb device (

Ego Shredder
Posts: 69
Joined: Fri Dec 29, 2006 2:42 am

Re: USB Copy size missmatch

Unread post by Ego Shredder » Sat Jan 13, 2018 7:54 pm

I did a large file transfer copy to another external USB 3.0 drive, and later found many missing files or corrupted files. So although it is very fast, it is also unreliable and hence why I asked Synology here on the forum to update the File Station to include CRC / MD5 hash checking. This feature does not appear to have been added yet. So I implemented another solution using a desktop PC, with some software called DiskBoss Ultimate/ With this I have created a few presets to handle my regular backup shares on the Synology NAS. This is quite fast too and more importantly....100% accurate and reliable.
Synology DS415+ DSM 5.1-5004 (bought December 2014) + 2x WD Red 6TB
Synology DS-101j DSM 2.0-0731 (bought February 2006)


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