ZFS on top of GELI

[Dan Naumov]

On Sun, Jan 10, 2010 at 6:12 PM, Damian Gerow <dgerow at afflictions.org> wrote:
> Dan Naumov wrote:
> : I am mostly interested in benchmarks on lower end hardware, the system
> : is an Atom 330 which is currently using Windows 2008 server with
> : TrueCrypt in a non-raid configuration and with that setup, I am
> : getting roughly 55mb/s reads and writes when using TrueCrypt
> : (nonencrypted it's around 115mb/s).
>
> I've been using GELI-backed vdevs for some time now -- since 7.2-ish
> timeframes.  I've never benchmarked it, but I was running on relatively
> low-end hardware.  A few things to take into consideration:
>
> 1) Make sure the individual drives are encrypted -- especially if they're
>   >=1TB.  This is less a performance thing and more a "make sure your
>   encryption actually encrypts properly" thing.
> 2) Seriously consider using the new AHCI driver.  I've been using it in a
>   few places, and it's quite stable, and there is a marked performance
>   improvement - 10-15% on the hardware I've got.
> 3) Take a look at the VIA platform, as a replacement for the Atom.  I was
>   running on an EPIA-SN 1800 (1.8GHz), and didn't have any real troubles
>   with the encryption aspect of the rig (4x1TB drives).  Actually, if you
>   get performance numbers privately comparing the Atom to a VIA (Nano or
>   otherwise), can you post them to the list?  I'm curious to see if the
>   on-chip encryption actually makes a difference.
> 4) Since you're asking for benchmarks, probably best if you post the
>   specific bonnie command you want run -- that way, it's tailored to your
>   use-case, and you'll get consistant, comparable results.

Yes, this is what I was basically considering:

new AHCI driver => 40gb Intel SSD => UFS2 with Softupdates for the
system installation
new AHCI driver => 2 x 2tb disks, each fully encrypted with geli => 2
geli vdevs for a ZFS mirror for important data

The reason I am considering the new AHCI driver is to get NCQ support
now and TRIM support for the SSD later when it gets implemented,
although if the performance difference right now is already 10-15%,
that's a reason good enough on it's own. On a semi-related note, is it
still recommended to use softupdates or is GJournal a better choice
today?

- Sincerely,
Dan Naumov