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From: Michael Christie <michael.christie@oracle.com>
To: Muneendra Kumar M <muneendra.kumar@broadcom.com>
Cc: linux-scsi@vger.kernel.org, Hannes Reinecke <hare@suse.de>,
	jsmart2021@gmail.com, emilne@redhat.com, mkumar@redhat.com
Subject: Re: [PATCH v3 05/17] scsi_transport_fc: Added a new rport state FC_PORTSTATE_MARGINAL
Date: Mon, 19 Oct 2020 11:19:22 -0500	[thread overview]
Message-ID: <CE70AE32-4318-4FB2-AEED-3606DEF59B79@oracle.com> (raw)
In-Reply-To: <3803E6D0-68D6-407F-80AB-A17E7E0E69E3@oracle.com>



> On Oct 19, 2020, at 11:10 AM, Michael Christie <michael.christie@oracle.com> wrote:
> 
> 
> So it’s not clear to me if you know the path is not optimal and might hit
> a timeout, and you are not going to use it once the existing IO completes why
> even try to send it? I mean in this setup, new commands that are entering
> the dm-multipath layer will not be sent to these marginal paths right?


Oh yeah, to be clear I meant why try to send it on the marginal path when you are
setting up the path groups so they are not used and only the optimal paths are used.
When the driver/scsi layer fails the IO then the multipath layer will make sure it
goes on a optimal path right so you do not have to worry about hitting a cmd timeout
and firing off the scsi eh.

However, one other question I had though, is are you setting up multipathd so the
marginal paths are used if the optimal ones were to fail (like the optimal paths hit a
link down, dev_loss_tmo or fast_io_fail fires, etc) or will they be treated
like failed paths?

So could you end up with 3 groups:

1. Active optimal paths
2. Marginal
3. failed

If the paths in 1 move to 3, then does multipathd handle it like a all paths down
or does multipathd switch to #2?


  reply	other threads:[~2020-10-19 16:19 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-15  3:27 [PATCH v3 00/17] scsi: Support to handle Intermittent errors Muneendra
2020-10-15  3:27 ` [PATCH v3 01/17] scsi: Added a new definition in scsi_cmnd.h Muneendra
2020-10-15  3:27 ` [PATCH v3 02/17] scsi: Added a new error code in scsi.h Muneendra
2020-10-15  3:27 ` [PATCH v3 03/17] scsi: No retries on abort success Muneendra
2020-10-16 18:37   ` Mike Christie
2020-10-19 19:05   ` Mike Christie
2020-10-19 19:26     ` Muneendra Kumar M
2020-10-20 19:53       ` Mike Christie
2020-10-20 20:18         ` Mike Christie
2020-10-21 18:51           ` Muneendra Kumar M
2020-10-15  3:27 ` [PATCH v3 04/17] scsi: Added routine to set/clear SCMD_NORETRIES_ABORT bit for outstanding io on scsi_dev Muneendra
2020-10-15  3:27 ` [PATCH v3 05/17] scsi_transport_fc: Added a new rport state FC_PORTSTATE_MARGINAL Muneendra
2020-10-16 19:52   ` Mike Christie
2020-10-19 10:47     ` Muneendra Kumar M
2020-10-19 16:10       ` Michael Christie
2020-10-19 16:19         ` Michael Christie [this message]
2020-10-19 17:16           ` Hannes Reinecke
2020-10-19 17:31             ` Muneendra Kumar M
2020-10-19 18:55               ` Mike Christie
2020-10-19 19:03                 ` Muneendra Kumar M
2020-10-20 18:24                   ` Benjamin Marzinski
2020-10-20  6:03                 ` Hannes Reinecke
2020-10-19 18:03             ` Muneendra Kumar M
2020-10-19 18:44               ` Mike Christie
2020-10-19 18:55                 ` Muneendra Kumar M
2020-10-20 16:48                   ` Mike Christie
2020-10-20 17:19                     ` Muneendra Kumar M
2020-10-20 18:44                       ` Benjamin Marzinski
2020-10-20 18:14                   ` Benjamin Marzinski
2020-10-15  3:27 ` [PATCH v3 06/17] scsi_transport_fc: Added store fucntionality to set the rport port_state using sysfs Muneendra
2020-10-15 14:05   ` kernel test robot
2020-10-15 14:05     ` kernel test robot
2020-10-16 18:34   ` Mike Christie
2020-10-19 10:52     ` Muneendra Kumar M
2020-10-15  3:27 ` [PATCH v3 07/17] scsi:lpfc: Added changes to fc_remote_port_chkready Muneendra
2020-10-15  3:27 ` [PATCH v3 08/17] scsi:qla2xx: " Muneendra
2020-10-15  3:27 ` [PATCH v3 09/17] scsi:qedf: " Muneendra
2020-10-15  3:27 ` [PATCH v3 10/17] scsi:libfc: " Muneendra
2020-10-15  3:27 ` [PATCH v3 11/17] scsi:ibmvfc: " Muneendra
2020-10-15  3:27 ` [PATCH v3 12/17] scsi:fnic: " Muneendra
2020-10-15  3:27 ` [PATCH v3 13/17] scsi:bnx2fc: " Muneendra
2020-10-15  3:27 ` [PATCH v3 14/17] scsi:csio: " Muneendra
2020-10-15  3:27 ` [PATCH v3 15/17] scsi:bfa: " Muneendra
2020-10-15  3:27 ` [PATCH v3 16/17] scsi:zfcp: " Muneendra
2020-10-22 16:50   ` Benjamin Block
2020-10-15  3:27 ` [PATCH v3 17/17] scsi:mpt: " Muneendra

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