From: Jianlin Lv <iecedge@gmail.com>
To: Bart Van Assche <bvanassche@acm.org>
Cc: jejb@linux.ibm.com, martin.petersen@oracle.com,
paulmck@kernel.org, bp@suse.de, peterz@infradead.org,
will@kernel.org, rdunlap@infradead.org, kim.phillips@amd.com,
rostedt@goodmis.org, wyes.karny@amd.com, jianlv@ebay.com,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
linux-scsi@vger.kernel.org
Subject: Re: [PATCH] scsi: sd: support specify probe type of build-in driver
Date: Sat, 24 Jun 2023 19:45:36 +0800 [thread overview]
Message-ID: <CAFA-uR_jk6jCmf9DTebSVBRwtoLuXuyvf1Biq+OObqRVAOZbBw@mail.gmail.com> (raw)
In-Reply-To: <5b898dde-2f76-51af-5d2e-c4572719a5be@acm.org>
On Fri, Jun 9, 2023 at 12:23 AM Bart Van Assche <bvanassche@acm.org> wrote:
>
> On 6/7/23 19:51, Jianlin Lv wrote:
> > On Thu, Jun 8, 2023 at 1:07 AM Bart Van Assche <bvanassche@acm.org> wrote:
> >> On 6/7/23 08:55, Jianlin Lv wrote:
> >> I see two possible solutions:
> >> - Change the volume provisioner such that it uses disk references that do
> >> not depend on the probing order, e.g. /dev/disk/by-id/...
> >
> > Yes, The "/dev/disk/by-id/" can uniquely identify SCSI devices. However,
> > I don't think it is suitable for the volume provisioner workflow.
> > For nodes of the same SKU , a unified YAML file will be defined to instruct
> > the volume provisioner on how to manage the local disks.
> > If use WWID, it would mean that a unique YAML file needs to be defined
> > for each node. This approach becomes impractical when dealing with a large
> > number of work nodes.
> Please consider using the paths available in /dev/disk/by-path.
Sorry for the late reply.
I carefully checked the server in the production environment and found
some corner cases where there are differences in the dev/disk/by-path/ of
nodes with the same SKU. These differences are caused by inconsistent
target_numbers.
For example:
diff -y aa-by-path bb-by-path
pci-0000:86:00.0-scsi-0:3:86:0 -> ../../sda |
pci-0000:86:00.0-scsi-0:3:88:0 -> ../../sda
pci-0000:86:00.0-scsi-0:3:87:0 -> ../../sdb |
pci-0000:86:00.0-scsi-0:3:89:0 -> ../../sdb
pci-0000:86:00.0-scsi-0:3:88:0 -> ../../sdc |
pci-0000:86:00.0-scsi-0:3:90:0 -> ../../sdc
pci-0000:86:00.0-scsi-0:3:89:0 -> ../../sdd |
pci-0000:86:00.0-scsi-0:3:91:0 -> ../../sdd
pci-0000:86:00.0-scsi-0:3:90:0 -> ../../sde |
pci-0000:86:00.0-scsi-0:3:92:0 -> ../../sde
pci-0000:86:00.0-scsi-0:3:92:0 -> ../../sdf |
pci-0000:86:00.0-scsi-0:3:93:0 -> ../../sdf
pci-0000:86:00.0-scsi-0:3:93:0 -> ../../sdg |
pci-0000:86:00.0-scsi-0:3:94:0 -> ../../sdg
pci-0000:86:00.0-scsi-0:3:94:0 -> ../../sdh |
pci-0000:86:00.0-scsi-0:3:95:0 -> ../../sdh
I'm still not sure what causes the target_numbers to be different.
However, the existence of such corner cases makes /dev/disk/by-path
unusable for the volume provisioner, similar to /dev/disk/by-id/.
So, If it's not possible to configure disk serialization detection, then
it seems that implementing predictable disk names is the only option.
Jianlin
>
> Thanks,
>
> Bart.
next prev parent reply other threads:[~2023-06-24 11:45 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-06 5:12 [PATCH] scsi: sd: support specify probe type of build-in driver Jianlin Lv
2023-06-06 17:38 ` Bart Van Assche
2023-06-07 15:55 ` Jianlin Lv
2023-06-07 17:07 ` Bart Van Assche
2023-06-08 2:51 ` Jianlin Lv
2023-06-08 16:23 ` Bart Van Assche
2023-06-24 11:45 ` Jianlin Lv [this message]
2023-06-07 14:10 ` Christoph Hellwig
2023-06-08 3:10 ` Jianlin Lv
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