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Mon, 19 Oct 2020 18:55:15 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 09JIsqup073949; Mon, 19 Oct 2020 18:55:14 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3030.oracle.com with ESMTP id 348ahva634-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 19 Oct 2020 18:55:14 +0000 Received: from abhmp0007.oracle.com (abhmp0007.oracle.com [141.146.116.13]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 09JItDAk002522; Mon, 19 Oct 2020 18:55:13 GMT Received: from [20.15.0.8] (/73.88.28.6) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 19 Oct 2020 11:55:13 -0700 Subject: Re: [PATCH v3 05/17] scsi_transport_fc: Added a new rport state FC_PORTSTATE_MARGINAL To: Muneendra Kumar M , Hannes Reinecke Cc: linux-scsi@vger.kernel.org, jsmart2021@gmail.com, emilne@redhat.com, mkumar@redhat.com References: <1602732462-10443-1-git-send-email-muneendra.kumar@broadcom.com> <1602732462-10443-6-git-send-email-muneendra.kumar@broadcom.com> <5ca752c2-94e1-444a-7755-f48b09b38577@oracle.com> <3803E6D0-68D6-407F-80AB-A17E7E0E69E3@oracle.com> From: Mike Christie Message-ID: <8c59834c-e46c-fde3-13d7-b60a82452148@oracle.com> Date: Mon, 19 Oct 2020 13:55:12 -0500 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9779 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 phishscore=0 bulkscore=0 malwarescore=0 spamscore=0 mlxlogscore=999 mlxscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2010190126 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9779 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 priorityscore=1501 clxscore=1015 malwarescore=0 mlxscore=0 bulkscore=0 lowpriorityscore=0 phishscore=0 adultscore=0 mlxlogscore=999 impostorscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2010190126 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On 10/19/20 12:31 PM, Muneendra Kumar M wrote: > Hi Michael, > > >> >> >> 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? >> >> Actually, marginal path work similar to the ALUA non-optimized state. >> Yes, the system can sent I/O to it, but it'd be preferable for the I/O to >> be moved somewhere else. >> If there is no other path (or no better path), yeah, tough. > >> Hence the answer would be 2) > > > [Muneendra]As Hannes mentioned if there are no active paths, the marginal > paths will be moved to normal and the system will send the io. What do you mean by normal? - You don't mean the the fc remote port state will change to online right? - Do you just mean the the marginal path group will become the active group in the dm-multipath layer?