ZFS Encryption Speed (Ubuntu 23.10)

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As it became a custom, I retest ZFS native encryption performance with each new Ubuntu release. Here we have results for Ubuntu 23.10 on kernel 6.5 using ZFS 2.2.

Testing was done on a Framework laptop with an i5-1135G7 processor and 64GB of RAM. Once booted into installation media, I execute the script that creates 42 GiB RAM disk that hosts all data for six 6 GiB files. Those files are then used in RAIDZ2 configuration to create a ZFS pool. The process is repeated multiple times to test all different native ZFS encryption modes in addition to a LUKS-based test. This whole process is repeated again with AES disabled and later with a reduced core count.

Since I am testing on the same hardware as for 23.04 and using essentially the same script, I expected similar results but I was slightly surprised to see both raw read and write speed has been reduced by more than 10%. I am not sure if this is due to the new kernel, new BIOS, or some other combination of changes but the performance hit seems quite significant.

However, what I'm most interested in is not necessarily the actual speed but how it's impacted by encryption. As compared to last year, it seems each GCM encryption mode has taken a few percent hit. We're still talking about 2 GiB/s for both read and write so I'm not too worried.

Interestingly, while key size had more impact before, it seems that with 23.10 you can count on the same speed regardless if you select 128, 192, or 256 bit key.

If you don't have AES support and you need CCM, the news is not that good as that code path has gotten significantly worse. Unless you're stuck on an ancient CPU this is irrelevant I guess as you should never opt for CCM in the first place.

Using ZFS on top of LUKS has gotten slightly better when it comes to writes where it actually lagged the most behind the native ZFS. The improvement is significant but we're still talking about 30% lower speeds. On read size, there are no changes and it's the only area where LUKS wins over the native ZFS encryption.

For this release, I also experimentally tried to get power usage for each test run. I did the same by disconnecting the battery and measuring the power the laptop was drawing. This is not the most precise way of measuring it so I might be off but it looked as ZFS encryption was as efficient as it gets when it comes to the power usage.

To summarize, the native ZFS encryption is still live and kicking in Ubuntu 23.10 and might even provide some power usage advantages as compared to LUKS.

PS: You can find older tests for Ubuntu 23.04, 22.10, 22.04, 20.10, and 20.04.

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