CentOS - Jan 2012 - LUKS full disk Encryption question

From RHEL docs:
"The default implementation of LUKS in Red Hat Enterprise Linux is AES 
128 with a SHA256 hashing. Ciphers that are available are:

     AES - Advanced Encryption Standard - FIPS PUB 197
     Twofish (A 128-bit Block Cipher)
     Serpent
     cast5 - RFC 2144
     cast6 - RFC 2612"

My question is:
What will be the performance impact on my Celeron 1.73 GHz CPU and/or 
hdd speed?


-- 

Ljubomir Ljubojevic
(Love is in the Air)
PL Computers
Serbia, Europe

Google is the Mother, Google is the Father, and traceroute is your
trusty Spiderman...
StarOS, Mikrotik and CentOS/RHEL/Linux consultant

Ljubomir Ljubojevic <office at plnet.rs> wrote:
> What will be the performance impact on my Celeron 1.73 GHz CPU and/or 
> hdd speed?
Well, the usual "it depends on your [exact] environment" is the real
answer.

However from a subjective perspective I've found that the only time
that I've really noticed a performance impact is during lots of I/O,
such as a *large* tarball extraction. (Presumably writing a large file
would be similar.) Eclipse, for example, touches a huge amount of files
but encryption on the underyling filesystem is not generally noticable.
It can be more noticable on a single core, single thread CPU.

If you have a server doing significant continuous I/O, probably 
benchmarking is the only reasonable way to tell.

Devin
-- 
	There's too much blood in my caffeine system.

Ljubomir Ljubojevic writes:
>  From RHEL docs:
> "The default implementation of LUKS in Red Hat Enterprise Linux is AES
> 128 with a SHA256 hashing. Ciphers that are available are:
> 
>      AES - Advanced Encryption Standard - FIPS PUB 197
>      Twofish (A 128-bit Block Cipher)
>      Serpent
>      cast5 - RFC 2144
>      cast6 - RFC 2612"
> 
> My question is:
> What will be the performance impact on my Celeron 1.73 GHz CPU and/or 
> hdd speed?
> 
I can't give any numbers, but I've been using luks for years now and
while
it sure adds a performance hit I don't find it really noticeable 
(especially on latest cpus) during normal use (web browsing, emails, 
films, office etc). Think of it this way, that laptop is already slow, at 
least now it will be secure. :-)

On 01/07/2012 06:40 PM, Ljubomir Ljubojevic wrote:
> What will be the performance impact on my Celeron 1.73 GHz CPU and/or 
> hdd speed?
To further add to what has been said, check if your particular CPU
supports the AES-NI instruction set which should provide some
performance boost:

http://en.wikipedia.org/wiki/AES_instruction_set

Of course, that is, if you choose to use the AES cipher (the default).

HTH,
Jorge