I have a synology NAS and the only workaround I have found to mounting an HFS+ USB drive on it is to turn off journalling on the drive. Are there any dangers for data loss or corruption from doing so?
What is the problem you have been having? Have you asked Synology about it?
The point of a journalled system is to prevent data corruption in the event of a crash or power outage. So obviously, this is a level of protection that will be missing.
For general purposes, it may not matter. But: If you take your braces off because you've already got a belt, you can bet your trousers will still fall down.
I haven't asked Synology directly yet but when you plug in an HFS+ drive it doesn't recognise it. There are lots of forum posts asking when HFS+ support will be included in the Synology software.
Are you using DSM 4.2? I don't think I had an issue connecting up my Mac formatted HFS+ drive in an USB 3 enclosure to the USB port on my DS212j... but it has been awhile. I recall being surprised because I though it was going to ask to reformat it. I just had to set permissions if I recall correctly... hmmm... I can use the drive for TM backups, but that may just be a server thing.