# GELI performance with AES-NI



## Morbius (Apr 2, 2013)

Does anyone have any experience of how much AES-NI helps GELI performance? 

I need to replace a faulty Phenom II based system, and I mainly want to reduce power consumption, so a core i3 would be a good choice, but it lacks AES-NI. I trying to decide whether it's worth going to an i5, or maybe an amd piledriver.

With a software implementation I find that moving files without geli is several times faster than geli to geli transfers  even with 128bit AES-CBC.


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## vermaden (Apr 2, 2013)

@*Morbius*

When You have AESNI, then 256bit AES XTS is not a problem, not a performance hit.

If You do not have AESNI, then 128bit AES CBC is MAX what I recommend (and use without AESNI).


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## Morbius (Apr 2, 2013)

Have you measured the transfer rates for GELI vs ordinary UFS with AES-NI? 

I know AES-NI is very much faster than software AES, but I'm not certain that AES is a simple limiting factor, the CPU usage of GELI seems a bit low for that.


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## vermaden (Apr 3, 2013)

I only used both of these with ZFS and without AESNI.

256bit AES XTS was about 15 MB/s, while 128bit AES CBC is about 60-80MB/s on SSD.


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## throAU (Apr 3, 2013)

Morbius said:
			
		

> Does anyone have any experience of how much AES-NI helps GELI performance?



I haven't done testing, but Intel indicate that using the AES-NI instructions is good for a 20-30x throughput increase vs doing AES without using the hardware support.

Bear in mind that a low power CPU may not be quite so low power if it is thrashing the CPU to run AES, vs. a "higher power" CPU that is essentially sitting idle (and can thus spend more time asleep or in a low power state) due to AES-NI support.

YMMV, depends on your workload, etc.


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## Sebulon (Apr 3, 2013)

@Morbius

This might be an interesting read:
GELI Benchmarks

/Sebulon


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