Re: [PATCH 13/13] docs: nvme-multipath: Add FC-NVMe marginal state

[Randy Dunlap]

On 8/12/26 11:46 AM, Randy Dunlap wrote:
> 
> 
> On 8/12/26 11:13 AM, Jesse Taube wrote:
>> Adds documentation for the new marginal state for
>> NVMe over Fibre Channel. Documents how to check and reset the state,
>> as well as a description of how it affects multipath policies.
>>
>> Signed-off-by: Jesse Taube <jtaubepe@xxxxxxxxxx>
>> ---
>>  Documentation/admin-guide/nvme-multipath.rst | 17 +++++++++++++++++
>>  1 file changed, 17 insertions(+)
>>
> 
> 'make htmldocs' build warnings:
> 
> linux-next/Documentation/admin-guide/nvme-multipath.rst:35: WARNING: Title underline too short.
> 
> FC-NVMe
> ---- [docutils]
> linux-next/Documentation/admin-guide/nvme-multipath.rst:50: ERROR: Unexpected indentation. [docutils]

Some fixes below.

>> diff --git a/Documentation/admin-guide/nvme-multipath.rst b/Documentation/admin-guide/nvme-multipath.rst
>> index 97ca1ccef459..8df4235d4d10 100644
>> --- a/Documentation/admin-guide/nvme-multipath.rst
>> +++ b/Documentation/admin-guide/nvme-multipath.rst
>> @@ -31,6 +31,23 @@ To set the desired policy (e.g., round-robin), use one of the following methods:
>>     1. echo -n "round-robin" > /sys/module/nvme_core/parameters/iopolicy
>>     2. or add the "nvme_core.iopolicy=round-robin" to cmdline.
>>  
>> +FC-NVMe
>> +----

    -------

>> +On NVMe over Fibre Channel there is an additional state called `marginal`
>> +All policies will treat this path as offline and will not use it unless
>> +all other paths are marginal or unavailable. In that case, the policy will
>> +select the best path based on the policy.
>> +
>> +To see the current path state, use one of the following methods:
>> +   1. cat /sys/class/fc_host/host*/device/rport-*/fc_remote_ports/rport-*/port_state
>> +   2. cat /sys/devices/virtual/nvme-subsystem/nvme-subsys*/nvme*/state
>> +To reset a path to online use:
>> +   1. echo "Online" > /sys/class/fc_host/host*/device/rport-*/fc_remote_ports/rport-*/port_state
>> +
>> +The marginal state is caused by a
>> +FPIN-LI (Fabric Performance Impact Notification - Link Impact) event.
>> +FPIN-LI event counters can be seen with:
>> +   1. cat /sys/class/fc_host/host*/statistics/fpin_li*

The marginal state is caused by a
FPIN-LI (Fabric Performance Impact Notification - Link Impact) event.
FPIN-LI event counters can be seen with::

  cat /sys/class/fc_host/host*/statistics/fpin_li*


>>  NUMA
>>  ----
> 

-- 
~Randy