[dm-devel] [PATCH v3] libmultipath: update INFINIDAT builtin config

[Martin Wilck]

Arnon,

On Tue, 2017-10-17 at 10:55 +0300, Arnon Yaari wrote:
> Based on the manufacturer documentation:
> https://support.infinidat.com/hc/en-us/articles/202319222
> 
> INFINIDAT recommends round-robin path selector using
> a different path per IO. Timeout and path recovery values
> are adjusted for error-free hot upgrade scenarios.
> 
> Signed-off-by: Arnon Yaari <arnony at infinidat.com>
> +       .fast_io_fail  = 15,
> +       .dev_loss      = 15,

I apologize for coming back to this after more than a year.
I've been wondering about your dev_loss recommendation.

What is the rationale for setting dev_loss and fast_io_fail to the same
value, which is straight against the general recommendation? And what
is the reason for the aggressively low dev_loss value anyway? Device
loss and re-discovery is much more complex to handle for both the
kernel and multipathd than failure/reinstantiation. You are the only
vendor who recommends setting dev_loss less than the default of 600s. 

Could you share your reasoning please?

Regards,
Martin

-- 
Dr. Martin Wilck <mwilck at suse.com>, Tel. +49 (0)911 74053 2107
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