In my desire to limit the amount of power my Virtual Environment draws, I am in the midst of decommissioning my DLT4 Tape Libraries in favor of a DISC Blu-Safe which holds 15 50GB Read/Erasable (RE) Blu-Ray disks. This unit draws less power than my larger Dell PowerVault 128T or the Breecehill Q7 I used previously while also much smaller in size so it can fit better within my reduced rack space design. Lastly, this device is USB 2.0 based and not SCSI based. So attaching it directly to a VM like I could with my SCSI device is not an option.
Yet, I have never done this after the first attempts as tape devices attached to VMs are horrendously slow, require ESX host reboots if there are a problem, and a general problem to maintain. Things have gotten better over the years of using ESX for VMs with tapes but I prefer a higher speed solution for backup. So I used a dedicated VCB Backup Proxy which also contains the backup software that interacts with the DISC Blu-Safe.
The only caveat I have found so far is that with the software I am currently using (from DISC), a file cannot SPAN Blu-Ray disks like it can with tape devices. Hopefully, I will find better software soon to solve this problem.
The USB device does draw power but quite a bit less than the tape library as the tape library would constantly run the robot to check for tapes. No such actions are taking place within the DISC Blu-Safe.
So far since I have started this process, my electric bill has dropped by over $100 per month while electric costs have gone up almost 0.04 cents per KwH. This is a major savings for a small business. Over $1200 per year!