> -----Original Message----- > From: Bart Van Assche [mailto:bvanassche@xxxxxxx] > Sent: Friday, June 22, 2012 1:50 PM > To: Moger, Babu > Cc: linux-scsi; Hannes Reinecke > Subject: Re: [PATCH] scsi_dh_alua: Re-enable STPG for unavailable ports > > On 06/22/12 17:52, Moger, Babu wrote: > > > One concern, the spec also says.. > > ============================== > > The unavailable target port asymmetric access state is > > intended for situations when the target port accessibility to a logical unit > may be severely restricted due to SCSI > > target device limitations (e.g., hardware errors). Therefore it may not be > possible to transition from this state to > > either the active/optimized, active/non-optimized or standby states. > > ===================================================== > > > > What happens if we cannot transition to active/optimized, active/non- > optimized or standby states. > > Are we going to loop forever? From kernel side it looks ok. We are going > mark the path as failed. > > It depends on what the path checker from multipath is going to do. Do you > have any idea about it? > > > Good question. I'm not a multipath expert, but as far as I understand > the multipath user space software if activating a path fails after some > delay multipathd tries again to find a usable I/O path. I was worried that path checker will somehow think the "unavailable state" as good. That might trigger continues path activations. But that is not the case. Tested with tur checker. It detects the state correctly. We are good. See below. Jun 22 14:27:20 nilgiris multipathd: mpathg: sdh - tur checker reports path is down Jun 22 14:27:20 nilgiris kernel: sd 1:0:1:1: [sdh] Done: SUCCESS Jun 22 14:27:20 nilgiris kernel: sd 1:0:1:1: [sdh] Result: hostbyte=DID_OK driverbyte=DRIVER_OK Jun 22 14:27:20 nilgiris kernel: sd 1:0:1:1: [sdh] CDB: Test Unit Ready: 00 00 00 00 00 00 Jun 22 14:27:20 nilgiris kernel: sd 1:0:1:1: [sdh] Sense Key : Not Ready [current] Jun 22 14:27:20 nilgiris kernel: sd 1:0:1:1: [sdh] Add. Sense: Logical unit not accessible, target port in unavailable state Patch looks good. Reviewed-by: Babu Moger <babu.moger@xxxxxxxxxx> > > Bart. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
