"James Cassell" <fedoraproject(a)cyberpear.com> writes:
On Tue, 23 Dec 2008 10:01:28 -0500, Marc Schwartz
<marc_schwartz(a)comcast.net> wrote:
>
> I have a separate /boot partition outside the LVM, since that cannot be
> encrypted.
> Using hdparm to test sequential reads on the encrypted and unencrypted
> partitions, I get 30 MB/Sec on the former and 36 MB/Sec on the latter.
> So I am looking at a 15-20% hit on throughput and that has been pretty
> consistent over several releases.
Could the performance difference here be due to the partitions being
on different parts of the disk? Throughput is higher on the outside
of the disk (which is the logical beginning of the disk.) I don't
think you have done a fair benchmark.
Fair point and it is possible, but under prior releases (pre-F9), when I
had to do a manual config and I did not have all partitions other than
/boot encrypted, I got pretty similar results in throughput changes
across the partitions. There was a period of time when I did not have
'/' encrypted, but did have /home, swap, /tmp and /var encrypted as
separate partitions without using LVM.
Clearly a better comparison would compare the same partitions in an
unencrypted and encrypted configuration. Without going through some
config gyrations that's easier said than done.
I don't think that it is unreasonable to expect some level of
performance hit, albeit with multi-core systems, that should be lessened
and perhaps those who do not experience a notable reduction in throughput
are using such systems. I'll have one next year... :-)
Thanks James,
Marc