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From: Hannes Reinecke <hare@suse.de>
To: Alibek Amaev <alibek.a@gmail.com>
Cc: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org
Subject: Re: Block device naming
Date: Thu, 16 May 2019 16:07:43 +0200
Message-ID: <680c9440-f1c9-68d1-cc5a-17aa9071fcc1@suse.de> (raw)
In-Reply-To: <CA+TYKz1E3mJ0hDQcv19QAFgeWVA-ADLoHtGQ5hy8SFxHOfuqfQ@mail.gmail.com>

On 5/16/19 3:49 PM, Alibek Amaev wrote:
> I have more example from IRL:
> In Aug 2018 I was start server with attached storages by FC from ZS3
> and ZS5 (it is Oracle ZFS Storage Appliance, not NetApp and also
> export space as LUN) server use one LUN from ZS5. And recently on
> server stopped all IO on this exported LUN  and io-wait is grow, in
> dmesg no any errors or any changes about FC, no errors in
> /var/log/kern.log* /var/log/syslog.log*, no throttling, no edac errors
> or other.
> But before reboot I saw:
> wwn-0x600144f0b49c14d100005b7af8ee001c -> ../../sdc
> I try to run partprobe or try to copy from this block device some data
> to /dev/null by dd - operations wasn't finished IO is blocked
> And after reboot i seen:
> wwn-0x600144f0b49c14d100005b7af8ee001c -> ../../sdd
> And server is run ok.
> 
> Also I have LUN exported from storage in shared mode and it accesible
> for all servers by FC. Currently this LUN not need, but now I doubt it
> is possible to safely remove it...
> 
It's all a bit conjecture at this point.
'sdc' could be show up as 'sdd' after the next reboot, with no 
side-effects whatsoever.
At the same time, 'sdc' could have been blocked by a host of reasons, 
none of which are related to the additional device being exported.

It doesn't really look like an issue with device naming; you would need 
to do proper investigation on your server to figure out why I/O stopped.
Device renaming is typically the least likely cause here.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		   Teamlead Storage & Networking
hare@suse.de			               +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Mary Higgins, Sri Rasiah
HRB 21284 (AG Nürnberg)

  reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-16 12:26 Alibek Amaev
2019-05-16 12:33 ` Hannes Reinecke
2019-05-16 13:49   ` Alibek Amaev
2019-05-16 14:07     ` Hannes Reinecke [this message]
2019-05-17 11:24       ` Alibek Amaev

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