I've doing some testing on a system to identify the impact that Bitlocker Encryption has on the read/write performance and the results have been interesting to say the least; I'm hoping someone can help to explain my findings.
I'm using an entry level server with quad core Xeon E-2224 CPU and 16GB RAM which has Windows Sever 2016 Standard installed - and it's a totally fresh Windows install with all of the latest relevant drivers are installed.
My storage array is configured through the integrated controller on the motherboard and is across 4 x 10TB WD Enterprise disks configured as follows:
RAID Level | RAID5 |
Legacy Disk Geometry (C/H/S) | 65535/255/32 |
Strip Size | 64 KiB |
Full Stripe Size | 192 KiB |
Disk 0 | WDC WD102KRYZ-0 |
Disk 1 | WDC WD102KRYZ-0 |
Disk 2 | WDC WD102KRYZ-0 |
Disk 3 | WDC WD102KRYZ-0 |
I've provisioned a single large logical volume and I've created two partitions for my testing as follows:
Drive | Capacity | File System | Allocation Unit Size |
Y: | 100 GB | NTFS | 4096 bytes |
Z: | 25,600 GB | NTFS | 8192 bytes |
I ran an array of tests (results attached) on the volumes before encryption, then reformatted and encrypted the volumes and same tests again.
The results have been very interesting, I was expecting to see a small performance hit across all tests due to Bitlocker, but what I found was that some tests had a drastic performance decrease, in some cases up to 50%, and surprisingly some tests showed an increase in performance, in one case an increase of 60%.
Can anyone help to explain this? I'm thinking of running the tests again with another product to see if I get similar results, but what I'm using is fairly robust/reliable from my experience.
Findings are in the spreadsheet attached.
