Can confirm. Cloud sync is a resource hog, extremely slow, but what’s more important — stops syncing for no reason out of the blue. And it’s not that it runs out of memory or is resourced constrained in any other way. It exhibited the same behavior on DS1618+ with 32GB of ram as well. It’s just garbage software. Like pretty much any other piece of software they have ever shipped. It also floods the network with DNS requests — cloud sync on a single NAS was responsible for 70% of requests from the entire network (I filed bug about it, nothing changed of course).
IXSystems took a sane approach and just use rclone under the hood. no complaints.
Their other sync service — CloudStation Disk and later Drive — to sync between clients and the NAS is just same garbage. Among other things (being slow and not completing sync most of the time) it also used to dump debug level logs into my home folder. Hundreds of megabytes daily. I filed a bug, asking them to change default level and to tell me where to configure it. Turned out it was done on purpose, “to help troubleshoot customer issues” and it cannot be changed, because it’s hardcoded. Hardcoded!
To be fair, it seems there are two large divisions at Synology — gimmicky user facing software marketing fluff, and low level kernel and filesystem fellas. The former are useless. They seem like one overworked intern. The latter — jumped on the issues I were reporting and actually attempted to triage and fix them (that aforementioned NVME timeout). They did not, but at least they’ve tried.
I guess lesson learned here is not to believe anything marketing tells you, especially if you get it for free, and if you buy a nas — expect to use it as a nas, run applications elsewhere. The hardware on those higher end Synology is quite well designed, and if they only dropped that btrfs-over-mdadm business and switched to OpenZFS — that would have yielded a rather decent and uniquely efficient product, (customers could totrlate/ignore the crappy useless value add gimmicky apps)
Edit. And don’t get me started on HyperBackup. Please don’t use it.
It’s unstable trash as well. Imagine you start a backup and then you want to cancel that backup run. There is cancel button. You press it. And then it does something shady for the next 15 minutes. Why? Network interruptions and power failures won’t wait 15 min for it to gracefully stop. Which means it runs in a consistently inconsistent state, and this is absolute opposite of how you design — wait for it — backup software.
Btw Instead of cloud sync you can go iXSsystems route and just run rclone directly in DSM. It’s self contained executable and will work file.