[dm-devel] multipathd: Add 'sysfs' prioritizer

[Christophe Varoqui]

I was waiting to see your response to Ben's comment about the pref bit
default values and tunable.

On Fri, Jun 3, 2016 at 9:05 AM, Hannes Reinecke <hare at suse.de> wrote:

>
>
> On 05/31/2016 10:34 PM, Sebastian Herbszt wrote:
> > Hannes Reinecke wrote:
> >> Recent kernels have an 'access_state' attribute which allows
> >> us to read the asymmetric access state directly from sysfs.
> >>
> >> Signed-off-by: Hannes Reinecke <hare at suse.de>
> >> ---
> >>  libmultipath/discovery.c           | 33 +++++++++++++++++++++++++++++
> >>  libmultipath/discovery.h           |  2 ++
> >>  libmultipath/prio.h                |  1 +
> >>  libmultipath/prioritizers/Makefile |  3 ++-
> >>  libmultipath/prioritizers/sysfs.c  | 43
> ++++++++++++++++++++++++++++++++++++++
> >>  libmultipath/propsel.c             |  6 +++++-
> >>  multipath/multipath.conf.5         | 14 ++++++++++++-
> >>  7 files changed, 99 insertions(+), 3 deletions(-)
> >>  create mode 100644 libmultipath/prioritizers/sysfs.c
> >
> > How about just adding this to the alua prioritizer?
> > This new feature could then depend on a "sysfs" argument.
> >
> No. The 'sysfs' prioritizer is using the abstract kernel sysfs
> interface, for which every device handler provides the information.
> So in theory it's independent on the underlying device handler.
>
> However, only the ALUA device handler has been reworked to provide
> up-to-date information; for the other device handlers there is a
> risk of the sysfs information is getting out-of-date.
>
> Hence I've restricted the 'detect_prioritizer' algorithm to select
> 'sysfs' only if an ALUA system is present.
> But this doesn't imply in any way that the 'sysfs' prioritizer can be
> used only for ALUA systems.
>
> Christophe, what about merging the patch?
>
> Cheers,
>
> Hannes
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/dm-devel/attachments/20160603/ad94729d/attachment.htm>