Folks just want to make a public service announcement here for Synology Hyper Backup users (and maybe other source clients?). If your unRAID backup target share is set to use the cache drive, and your cache is smaller than the backup size, you're going to have a bad time.
I'm a bit of an unRAID noob, so I beat my head against the wall with this one for like weeks. I tried running rsync in a docker. I tried spinning up a VM. The logs on both end were pretty much useless. I was able to establish the connection and start the backup, but eventually it would always fail and the rsync daemon process would evaporate. I just happened to browse the cache drive and see the backup stuff stacking up there, and wondered why that was. Once I turned off cache for that share, it worked flawlessly.
Can anyone comment on potential workarounds to be able to utilize the cache drive in this scenario?