How to back up a Synology NAS with IDrive

I love my Synology NAS, and have all kinds of data on it: photos, movies, synced folders and backups of my other systems. The one thing it doesn’t do is handle off-site backup. Many people choose to buy a second Synology and put it at a friend’s house or some other off-site location, which is a great strategy, but not practical for me. Instead, I like IDrive, simply because there’s nothing else I know of that can hit the price point of ~$100/yr for 10TB.

The problem is, it’s not nearly as plug-and-play as C2 or other HyperBackup target options. The first time I set it up, I selected the couple most important folders as a basic start but I was greeted with a “350TB” backup set. Note that my NAS only has about 4TB consumed on it. That simply wouldn’t do.

Short Version: Go to “preferences” in the dropdown at the top-right of the IDrive synology web interface, and click on the “Exclude” tab. Add “#recycle” and “#snapshot” to the “partial names” pane. If you use Active Backup for Business, you should also only back up the “@ActiveBackup” directory, and NOT the “ActiveBackupData” directory.

The two key systems on DSM that can result in massive apparent backup jobs are Btrfs snapshotting and Active Backup for Business’ versioning system.

Btrfs snapshots allow you to freeze-frame the filesystem as frequently as you like, and subsequent changes simply add to the existing data. Space can be freed up by deleting snapshots, which releases for reuse any space on disk required by only that snapshot.

By default, snapshots are transparent and simply copy/pasting the whole folder will miss any snapshots entirely. However DSM allows exposing snapshots in a “#snapshot” folder at the root of a share, which contains a list of folders named by the timestamp of the snapshot.

If IDrive is allowed to back up this special directory, it’ll massively multiply the backup set file size.

Similarly, “ActiveBackupData” is full of “virtual” files representing the backed up data at the time of each job run with no apparent deduplication, while all the underlying data lives in “@ActiveBackup”.

Instead of backing up the virtual files, the proper strategy is, in the event of a recovery, restore the “@ActiveBackup” directory and then “relink” that directory in ActiveBackup storage settings, per this guide:


  1. Brian Baker
    February 19, 2024

    What plan are you using with IDrive? I have been using Hyper Backup with Backblaze’s B2 storage, but it’s been getting past $40/month lately which feels pricey for personal backup. It looks like IDrive also offers S3 compatible storage which might make for an easy transition, but not really much cheaper.

  2. February 19, 2024

    I’m using IDrive Personal, hence needing to do the file-based backup with their synology package. The S3 compatible storage you could use with HyperBackup would be convenient, but yeah, its a lot pricier. Personal is $150/yr for 10TB which seems like a decent deal in the first place, but they also constantly run promotions. The first year, I got the 5TB tier for $5, then the second year it was about to renew at list price but they had another “upgrade to 10TB for just $5 for the year!” Since then I’ve been paying $100/yr for 10TB which is still some grandfathered promotion, and the S3-compatible product is 5x as expensive.

  3. June 13, 2024

    The trick of excluding ActiveBackupData really saved my day. Thanks!
    BTW, as iDrive doesn’t support deduplication [1] and time travel, an idea is to attach an external USB HDD as HyperBackup destination, and sync that USB HDD to cloud (iDrive in this case).

    [1] I’ve searched the web, a NYTimes article says it supports deduplication for accounts created after Sept 22, 2021, but I can’t find any other reference. The NYTimes article link is at

  4. June 13, 2024

    Thanks @matthew!

    My understanding is that my iDrive account DOES support deduplication, and it seems to me like the deduplication inherent in ActiveBackup should be taking care of me as well. But I’d be interested to try your way. I know I seem to have a highly variable backup job. Even if I don’t do much of anything on my laptop but it’s alive for the first night in a week for its ActiveBackup, it seems like the next idrive job is quite a bit larger than “stuff that changed on my laptop.” Maybe if I do the hyperbackup intermediary that’d be less of an issue (and restore more straightforward too!)

    I’d kind of been discounting it based on scale but I guess the external doesn’t have to be as big as my NAS, just as big as my backup.

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