My backup server has a ASRock H370M-ITX/AC motherboard in it and at the time of these benchmarks 3x6TB Seagate Ironwolf SATA disks.
I run Veeam and used the SATA disks as my backup repository.
My original configuration was 2x6TB Ironwolfs in a RAID0 (using Microsoft Storage Spaces) with Bitlocker enabled. This worked perfectly fine and I had no performance issues.
A project I was working on required me to add some redundancy to my backup storage so I purchased the 3rd disk and re-configured the Microsoft Storage Space as a RAID5 and re-enabled Bitlocker. Since then I had nothing but performance issues. When two backup jobs ran at the same time the server became nearly unresponsive. The jobs still ran and completed but it was very difficult to use the server and jobs took longer with the RAID5 configuration than the RAID0 configuration. A performance difference makes sense but this amount seemed abnormal.
I ended up with a spare LSI MegaRAID 9270-8i I couldn’t sell so I decided to throw it into my backup server and try running the above configuration with hardware RAID but before I did that, I ran some benchmarks.
As you can see BitLocker has a huge negative impact on this configuration even though the server is running a Intel Core i3-8100 which has hardware acceleration built in for encryption.
You can probably guess how this is all going to end now.
First a 3 disk RAID0:
Last but not least, a 3 disk RAID5:
It’ still a ~70% hit on sequential writes but the server is completely usable and backup jobs run at the speeds I would expect over 1GBe.