Hannes Reinecke wrote:
malahal@xxxxxxxxxx wrote:
John Hughes [john@xxxxxxxxx] wrote:
I want to turn queue_if_no_path off and use
polling_interval 5
no_path_retry 5
because I've had problems with things hanging when a lun "vanishes"
(I deleted it from my external raid box).
But whatever I put in /etc/multipath.conf when I do a "multipath -l"
or "multipath-ll" it shows:
Did you reload the mapper table?
360024e80005b3add000001b64ab05c87dm-28 DELL ,MD3000
[size=68G][features=1 queue_if_no_path][hwhandler=1 rdac]
\_ round-robin 0 [prio=3][active]
\_ 3:0:1:13 sdad 65:208 [active][ready]
\_ round-robin 0 [prio=0][enabled]
\_ 4:0:0:13 sdas 66:192 [active][ghost]
Which is entirely correct. The 'queue_if_no_path' flag _has_ to
be set here as we do want to retry failed paths, if only for
a limited amount of retries.
The in-kernel dm-multipath module should handle the situation correctly
and switch off the queue_if_no_path flag (= pass I/O errors upwards)
when the amount of retries is exhausted.
As far as I can tell it retries forever (even with polling_interval 5
and no_path_retry 5). The mdadm raid10 built on top of the multipath
devices hangs, even /proc/mdstat hangs.
You're saying that without queue_if_no_path multipath basicly won't work
- mdadm will see I/O errors on multipath devices if a path fails?
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