Re: [PATCH v2] nvme-fc: don't require user to enter host_traddr

From: James Smart
Date: Thu Nov 30 2017 - 11:45:05 EST


On 11/30/2017 7:12 AM, Johannes Thumshirn wrote:
One major usability difference between NVMf RDMA and FC is resolving
the default host transport address in RDMA. This is perfectly doable
in FC as well, as we already have all possible lport <-> rport
combinations pre-populated so we can pick the first lport that has a
connection to our desired rport per default or optionally use the user
supplied lport if we have one.

Signed-off-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
Cc: James Smart <james.smart@xxxxxxxxxxxx>

This is unnecessary and can create weird configurations. It assumes connections are manually created. The weirdness is: a) an admin has to know there are multiple paths in order to connect them and be intelligent on how to get the complex name strings and try to know what connections are already in existence;Â b) if a users has a connectivity loss beyond dev_loss_tmo or ctlr_loss_tmo such that the controller is terminated, they must manually issue the connec commands again; and c) those un-knowledgeable users will unknowingly find that their multiple paths aren't connected and the system will gang up on the host adapter detected on the system with connectivity. All things unexpected and not what occurs with FC and SCSI and which will result in system support calls.

If the system uses the FC auto-connect scripts things will be properly connected across all paths connected to the subsystem - automatically, including resume after an extended connectivity loss - and the system will behave just like FC does with SCSI.

I see no reason to add this patch. Please move away from manual configuration.

-- james