Can you keep a secret? This encrypted drive can...

Ralf Senderek ralf at senderek.com
Sat Nov 4 05:35:15 EST 2006


On Thu, 2 Nov 2006, Alexander Klimov wrote:

> I guess many people here have tried full disk encryption for
> themselves, do you notice any difference in performance or not?

Yes and no!

I use dm-crypt on a Linux laptop with FC5.

On the encrypted filesystem:

# > df
/dev/mapper/secure      309895    213342     80553  73% /secure

# > time dd if=/dev/zero of=cryptogram bs=1MB count=50
50+0 records in
50+0 records out
50000000 bytes (50 MB) copied, 1.96366 seconds, 25.5 MB/s
dd if=/dev/zero of=cryptogram bs=1MB count=50  0.00s user 0.52s system 25%
cpu 2.023 total

On the unencrypted filesystem:

# > time dd if=/dev/zero of=cryptogram bs=1MB count=50
50+0 records in
50+0 records out
50000000 bytes (50 MB) copied, 0.216106 seconds, 231 MB/s

real    0m0.257s
user    0m0.000s
sys     0m0.252s

The factor 9.05 making the the unencrypted filesystem faster than the
encrypted one really does not make a difference for me for anything I do.
I'd be happy with 1 MB/s and I got 25! (using AES-256)

Regards

     Ralf Senderek

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