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Synology Cloud Drive Backup  



Hi folks.

I'm trying to use Synology Cloud Drive to backup my Photos libraries.  I have a total of 1.46Tb to back up on an external drive on my iMac, and my Synology is a DS2115j with 2 x 2Tb disks configured in a 1.8Tb volume.  I started with a clean build on the Synology.

Here's the question:  I've been backing up for a couple of days and I've run out of space on the NAS.  According to the Cloud Drive Client I have over 200k files still to backup.  So - how can I have run out of space on the Synology?  Is there something about Photos libraries that means they take up much more space on Synology than on my iMac?  Any other ideas?


5 Answers

You didn't say how you are using Synology Drive to "backup" your photo library.  Did you just drag your photo library from ~/Pictures into your Synology Drive folder?  That approach probably won't work.  Apple uses some of the fancy features available in HFS+ and APFS to do things in the Photos library (ex Hardlinks).  Equivalent versions of those features don't exist for the synology filesystems (EXT4 or BTRFS), or won't be interpreted correctly when trying to send the data to the synology.  So you will get unpredictable results.  Generally speaking, Apple Photos doesn't support accessing a photo library over a LAN connection (for these same reasons).  The only supported options are having the photos library on your internal HD, or on an external HD that is directly attached to your mac and formatted as HFS+ or APFS.

Also, Synology Drive is a syncing service, not a backup service.  A sync is not a proper backup!  If you accidentally delete something, the sync service will faithfully replicate that to the synced copy.  Unless the sync service has some sort of versioning system (which takes up more space), there won't be a way to roll-back to a prior state.

Note that it is possible to backup your Photos library using proper backup software.  For example, ARQBackup can backup your mac to the synology, using either the SFTP or SMB protocol.  Or you an configure your synology to offer a TimeMachine destination, and backup your Photos to it using TimeMachine.

Also note that backups grow over time.  It doesn't seem like you've provided enough space on your synology to leave you headroom for backups to grow over time.

This post was modified 4 weeks ago by cpragman

I’m using the Synology Drive client which has a backup service as well as a sync service. I’ve configured the backup service to backup my Photo libraries. 

I hadn't made the connection with hard links - I now get why my photo libraries take up so much more space on the Synology - so thanks for that @cpragman.

I'm going to give Arq a try.  My end goal is to backup from my iMac to the Synology over the internet - though it is currently connected to the iMac locally over ethernet so I can do the initial backup more quickly.  Any advice?


ARQ can backup to an SFTP destination (that’s what I do). 
make SFTP active on your Synology. Make a shared folder in the Synology for your ARQ destination. Optionally put a quota on this folder. On the Synology, Create a user with strong password that you will use for your ARQ user. Set permissions so this ARQ user can’t access any other folders or services. There’s also an advanced setting (I forget where) that lets you put that user in a chroot jail, which I also recommend. 

use a dynamic dns service to register a domain name that points to your home router. For connecting when inside your house, add a manual entry to your router’s dns that points to the internal address of your Synology. Thus way you (and ARQ) can access the Synology using the same url, whether you are home or traveling. 

when you feel like you’ve got security setup right on the Synology, forward the SFTP port in your router to the Synology. Check the Synology firewall settings for some ways to harden security. 

I'm nearly there I think. Successfully backing up and restoring over the internet using SFTP following your advice - so thanks for that! Re the dynamic DNS bit - I understand why that is needed but is it possible to use QuickConnect instead?


Not sure about your quick connect question. I keep it turned off just to reduce the attack surface of my machine. Also, it might only work for http requests, and not ssh/sftp. Don’t know. 

I found that Synology offers a DDNS service - "" and I'm using that.

So, this is now doing exactly what I want. I can seed a full backup of my MacOS photos libraries using gigabit ethernet, and I can then take that Synology to an offsite location and backup the deltas over the internet. Thanks so much for your help - much appreciated.


Glad to hear it!