On Fri, Feb 12, 2016 at 09:34:59AM -0500, Jes Sorensen wrote:
> Mikael Abrahamsson <swmike@xxxxxxxxx> writes:
> > On Thu, 11 Feb 2016, Marc MERLIN wrote:
> >
> >> But can someone confirm that indeed if I have a single md device,
> >> and 4 CPUs, my throughput is not limited by a single CPU decrypting
> >> the device?
> >
> > There have been multiple discussions about this over time, and since
> > you didn't qualify "not good" with a number, it's hard to say if this
> > is your problem or not.
>
> About a year ago when I last received a new laptop, I put btrfs on top
> of luks - it was a rather miserable experience. The system would freeze
> up and be really slow.
>
> I believe the issue was btrfs not acting well with crypto underneath it,
> and there was hallway talk confirming this but I have no hard data. In
> the end I gave up and put my /home on xfs on top of LUKS and used btrfs
> for the uncrypted portions.
>
> It may be the btrfs with crypto issues have been resolved since then.
Thanks all for the feedback and experiences.
"not good" is indeed subjective, I can see the kernel hanging for a few
seconds at a time under heavy I/O and cron jobs taking too long.
I'm indeed going to just rebuild the FS with a new layout, and try
bcache in the process.
I still need to figure out what I should use as best chunk size for
mdadm, whether this is reasonable:
cryptsetup luksFormat --align-payload=8192 -s 256 -c aes-xts-plain
and see if there are tuning parameters in bcache I should worry about.
Thanks,
Marc
--
"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
Microsoft is to operating systems ....
.... what McDonalds is to gourmet cooking
Home page: http://marc.merlins.org/ | PGP 1024R/763BE901
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