On 11/08/2016 07:52 PM, Xose Vazquez Perez wrote:
On 07/15/2016 08:48 AM, Hannes Reinecke wrote:
Recent kernels have an 'access_state' attribute which allows
us to read the asymmetric access state directly from sysfs.
Hi Hannes,
with this patch it's impossible to select/autodetect ALUA.
sysfs always takes precedence over alua.
"detect_prio no" was added to overrides section, to make
it work again.
SLES 12-SP2
Thank you.
But this was precisely the idea.
(After all, it says 'auto-detect', right?)
For ALUA-capable arrays we have a reliable priority detection with the
ALUA device-handler.
So it's far preferable to use the sysfs-provided information (as they
are populated by the ALUA device-handler); the ALUA prioritizer in
multipath-tools will be used as a fallback in case the device handler
isn't loaded or the sysfs files are not present.
Using the sysfs handler has the neat side effect that you don't need to
do I/O for detecting the priority, thereby eliminating one possible
cause for multipath being stuck during failover.
Cheers,
Hannes
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Dr. Hannes Reinecke Teamlead Storage & Networking
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