[dm-devel] [PATCH 14/15] multipath-tools: replace queue-length by default selector

[Xose Vazquez Perez]

On 08/11/2016 07:58 AM, Hannes Reinecke wrote:

> On 08/10/2016 06:20 PM, Xose Vazquez Perez wrote:

>> service-time is more advanced, and it works better in asymmetric and
>> symmetric(corrected) environments.

>> -		.selector      = "queue-length 0",

> I would _not_ do this, unless tested on the real hardware.
> Just claiming 'the other one is more advanced' is not enough here.

service-time works better in any wild environment, different adapters or
different links speeds and any kind of load, aka the Production Environment.
I guess that manufacturers' tests are done in ideal conditions(PV=nRT).

Anyhow, the default path selector algorithm does not depend, by no means, of
any array settings or hardware. It's only related to the Linux host and
its environment.

How PURE/FlashArray and XtremIO/XtremApp were tested? Is there anything
wrong with service-time?