ZFS on top of GELI / Intel Atom 330 system

[Dan Naumov]

Thank you for your numbers, now I know what to expect when I get my
new machine, since our system specs look identical.

So basically on this system:

unencrypted ZFS read: ~70 MB/s per disk

128bit Blowfish GELI/ZFS write: 35 MB/s per disk
128bit Blowfish GELI/ZFS read: 24 MB/s per disk

I am curious what part of GELI is so inefficient to cause such a
dramatic slowdown. In comparison, my home desktop is a

C2D E6600 2,4 Ghz, 4GB RAM, Intel DP35DP, 1 x 1,5TB Seagate Barracuda
- Windows Vista x64 SP1

Read/Write on an unencrypted NTFS partition: ~85 MB/s
Read/Write on a Truecrypt AES-encrypted NTFS partition: ~65 MB/s

As you can see, the performance drop is noticeable, but not anywhere
nearly as dramatic.


- Dan Naumov


> I have a zpool mirror on top of two 128bit GELI blowfish devices with
> Sectorsize 4096, my system is a D945GCLF2 with 2GB RAM and a Intel Arom
> 330 1.6 Ghz dualcore. The two disks are a WDC WD10EADS and a WD10EACS
> (5400rpm). The system is running 8.0-CURRENT amd64. I have set
> kern.geom.eli.threads=3.
>
> This is far from a real benchmarks but:
>
> Using dd with bs=4m I get 35 MByte/s writing to the mirror (writing 35
> MByte/s to each disk) and 48 MByte/s reading from the mirror (reading
> with 24 MByte/s from each disk).
>
> My experience is that ZFS is not much of an overhead and will not
> degrade the performance as much as the encryption, so GELI is the
> limiting factor. Using ZFS without GELI on this system gives way higher
> read and write numbers, like reading with 70 MByte/s per disk etc.
>
> greetings,
> philipp