On 04/28/2016 09:23 AM, Laurence Oberman wrote:
We still suffer from periodic complaints in our large customer base
> regarding the long recovery times for dm-multipath.
Most of the time this is when we have something like a switch
> back-plane issue or an issue where RSCN'S are blocked coming back up
> the fabric. Corner cases still bite us often.
Most of the complaints originate from customers for example seeing
> Oracle cluster evictions where during the waiting on the mid-layer
> all mpath I/O is blocked until recovery.
We have to tune eh_deadline, eh_timeout and fast_io_fail_tmo but
> even tuning those we have to wait on serial recovery even if we
> set the timeouts low.
Lately we have been living with
eh_deadline=10
eh_timeout=5
fast_fail_io_tmo=10
leaving default sd timeout at 30s
So this continues to be an issue and I have specific examples using
> the jammer I can provide showing the serial recovery times here.
Hello Laurence,
The long recovery times you refer to, is that for a scenario where all
paths failed or for a scenario where some paths failed and other paths
are still working? In the latter case, how long does it take before
dm-multipath fails over to another path?
Thanks,
Bart.
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