Strange Drobo S behavior please advise


I have a first generation Drobo S that is used as a backup unit for my video files. It filled with 5x 4TB drives and has about 25% space free. I have been trying to back up my files to it and it seems to be going painfully slow. I notice on the WD passport drive that the activity light flashes for a few seconds and then stalls for minutes then flashes again while the Drobo S activity light is solid. I’ve restarted the unit, have the latest firmware.

Can anyone please help me figure out why its running the way it is? It seems like its not transferring data smoothly.

Thanks so much!

Is the progress bar showing consistent progress when copying your data? Do you have any other background task that are running on your computer?

It is definitely slower to copy files this way as the files are first copied to your computer then copied to your WD external drive. Even more so if these devices are connected via USB.