Most of our users are on Catalina, and we are using a QNAP NAS with about 45TB of storage to backup about 75 users at our main site. Recently, most of our users backups have failed using standard Time Machine and AFP protocol, and QNAP recommended using SMB share and Time Machine. We have tried this with same results. Even if a backup completes and seems to be working for few days, it seems all are getting error "Time Machine completed verification of your backup …, and to improve reliability Time Machine must create a new backup and the cycle begins. You only have option to Start New Backup. I have tried deleting the local time machine.plist file and starting over, but still seems to have same issues, and looking online seems a lot of other vendors like Synology have users reporting same or similar issues since Catalina (some even Mojave upgrade). It seems at some of our smaller campuses that users backing up to Apple Time Capsule aren’t experiencing the issue, and wondering if anyone else seeing these issues and found away to fix. Thanks in advance.
I love Synology, QNAP, and others… but doing Time Machine to anything but an Apple Time Capsule or directly attached drive is a hack. I’ve had great reliability with Synology, and still use it often, but you have to accept the risk that an update from Apple can break it until the next software update for the NAS brings a fix.
We ditched Time Machine about 6 months ago for Backblaze and been happy ever since. Our issue was bandwidth and backups never completing before the user was off-network and Time Machine would just fail and keep completely starting over.
We had similar issues, but were backing up to a virtual macOS server running the time machine service. We ended up cutting out local machine backups altogether in favor of having our users use the OneDrive client and having them put all their files in there. 1 TB for each user hasn’t filled up yet :-). Our macs all have a standard image, so if a user needs a new Mac or a drive fails, we just replace the machine, image it, and load OneDrive.