Array encryption and recommended hardware performance

[MadDiplomat]

I've been reading about the encryption feature but did not find much information about the expected performance hit.

 

I'm worried that my aging 4-core system would be far too weak for it and that I should not even bother trying turning it on: B75 Pro3-M, i7-2600K, 4x4GB DDR3.

 

I use 1 parity + 5 data disks without a cache drive. By using turbo writes, my write speed to the array is limited by the gigabit ethernet. I can already hit 50% CPU utilization if I, for example, use mc to copy lots of data and run some background docker apps. I'm thinking I don't have much headroom and seeing my speed drop to something like 50 MB/s with encryption would not be great at all.

 

Thank you for sharing any experience or feedback.

[JorgeB]

If the CPU supports the AES-NI instruction set you shouldn't notice any significant performance hit, and IIRC your CPU does.

[esaru]

Your CPU does indeed have the AES-NI instruction set. I'd just go ahead and encrypt! 

 

https://ark.intel.com/content/www/us/en/ark/products/52214/intel-core-i7-2600k-processor-8m-cache-up-to-3-80-ghz.html

Intel® AES New Instructions - Yes

[MadDiplomat]

Thanks for the info. I’m preparing to build my second unraid machine and once that’s done, I will encrypt the 2600K one. I’ll report back whether there was any impact on the speed, but it will probably take me a few weeks :)

[MadDiplomat]

I'm happy to report that the effect of using encryption (xfs) on all array data disks and all cache pools has been negligible in my situation. Not only are the read/write speeds unchanged, the CPU utilization remains comparable to before. Note that I am not running any VMs, only a couple of dockers (Plex, downloaders ...).

 

I only noticed one peculiarity, but I'm unsure if encryption had anything to do with it. To avoid shuffling the data and encrypting the drives one by one, I copied the entire array to another NAS, deleted all partitions and set a new configuration (essentially building the array anew) and then copied everything back. When I initiated the formatting of the 5 data drives to xfs-encrypted, the CPU usage spiked to 100% on all cores for about 3-5 minutes. Within this timeframe, the UnRAID web interface was completely unresponsive for about 2 minutes. However, this may simply be considered normal operation? The previous time I built an array from scratch and formatted all the drives was in 2011, so I really can't make a comparison  

Edited May 26, 2021 by MadDiplomat
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