ZFS on top of GELI

[Roland Smith]

On Sun, Jan 10, 2010 at 05:08:29PM +0200, Dan Naumov wrote:
> Hello list.
> 
> I am evaluating options for my new upcoming storage system, where for
> various reasons the data will be stored on 2 x 2tb SATA disk in a
> mirror and has to be encrypted (a 40gb Intel SSD will be used for the
> system disk). Right now I am considering the options of FreeBSD with
> GELI+ZFS and Debian Linux with MDRAID and cryptofs. Has anyone here
> made any benchmarks regarding how much of a performance hit is caused
> by using 2 geli devices as vdevs for a ZFS mirror pool in FreeBSD (a
> similar configuration is described here:
> http://blog.experimentalworks.net/2008/03/setting-up-an-encrypted-zfs-with-freebsd/)?
> Some direct comparisons using bonnie++ or similar, showing the number
> differences of "this is read/write/IOPS on top of a ZFS mirror and
> this is read/write/IOPS on top of a ZFS mirror using GELI" would be
> nice.
> 
> 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).

Although I cannot comment on ZFS, my $HOME partition is UFS2+geli. Reads (with
dd) of uncached big[1] files are ~70MB/s. Reading an unchached big file from a
non-encrypted UFS2 partition is ~120MB/s. Note that the vfs cache has a huge
influence here; Repeating the same read will be 4 – 7 times faster!

The sysctls for ZFS chaching will probably have a big impact too.

Roland

[1] several 100s of MiB.
-- 
R.F.Smith                                   http://www.xs4all.nl/~rsmith/
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