"Encryption eats a lot of CPU cycles, which have become a concern after Spectre/Meltdown, and the stability of sw based encryption is shaky at best."
With LUKS on most CPU's the encryption has very little overhead at it uses the AES instructions in the CPU (so basically it is done in hardware).
One set of benchmarks I saw has the encrypted disks as faster than non-encrypted. Last time I read it it was thought this might just be to do with newer more optimal code in the LUKS code...but I'll take that with a pinch of salt.
http://dentarg.it64.com/content/luks-and-intel-aes-ni-performance-part-2
I think realistically it is likely in the 5% region of CPU overhead.
Biting the hand that feeds IT
