We have a 2012 R2 server with a 16TB iSCSI drive mapped that has deduplication enabled. We are using it for long term archives of backups of Hyper-V virtual machines. Veeam is the application doing the backups.
It was working normally for about 2 months or so, but for the past 3 weeks it hasn't optimized any new files. It has been stuck at 233 files optimized for the past 3 weeks. During troubleshooting I saw there were about a dozen or so ddpcli.exe processing running. It wouldn't end them, so I stopped the deduplication service and it was stuck at stopping, but I let it run overnight and when I checked it in the morning it was up to 238 of 450 files optimized. That was two days ago and there hasn't been any more files optimized. I tried doing a stop-dedupjob to stop all jobs, then run a start-dedupjob -type optimization -full and let it run overnight but still no more progress. I also did a garbage collection and scrubbing. That freed up some space, but no more files optimized.
Any ideas on what else I can do?