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From: Jeremy Linton <jlinton@tributary.com>
To: Hannes Reinecke <hare@suse.de>
Cc: Linux Scsi <linux-scsi@vger.kernel.org>,
	"Elliott, Robert (Server Storage)" <Elliott@hp.com>
Subject: Re: [PATCH] Use a more selective error recovery strategy based on device capabilities
Date: Wed, 13 Feb 2013 09:46:13 -0600	[thread overview]
Message-ID: <511BB545.7060600@tributary.com> (raw)
In-Reply-To: <511B8FBF.9000705@suse.de>

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On 2/13/2013 7:06 AM, Hannes Reinecke wrote:

> But unfortunately it failed the reality check; of my zoo of storage arrays
> only NetApp OnTap 8.X and HP P2000 supports the REPORT SUPPORTED TASK
> MANAGEMENT FUNCTIONS command. None of the others (HP EVA, NetApp E-Series,
> EMC Clariion CX-3) do.

	I'm not really surprised. I've had better luck with devices that report
compliance with more recent versions of the specification. Of the those, I
would guess slightly more than 50% support it. That includes tape drives,
changer devices, and raid controllers. Of the ones I've tested that support
it, they almost always report 0xDA for the first byte. Which correspond to
abort task, abort task set, clear task set, lun reset and target reset.

	The patch also includes some "reasonable" defaults based on SCSI version,
which I think vastly improves the overall error handling situation. Querying
the device is just the last little icing.

	But its a chicken and egg thing, the command is optional, hardly anyone sends
it, so few of the device manufactures have implemented it.









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  reply	other threads:[~2013-02-13 15:46 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-12 18:19 [PATCH] Use a more selective error recovery strategy based on device capabilities Jeremy Linton
2013-02-12 20:57 ` Elliott, Robert (Server Storage)
2013-02-12 22:00   ` Jeremy Linton
2013-02-13 13:06 ` Hannes Reinecke
2013-02-13 15:46   ` Jeremy Linton [this message]
2013-02-14  2:43     ` Michael Christie
2013-02-14 20:57       ` Jeremy Linton
2013-02-14 23:42         ` Elliott, Robert (Server Storage)
2013-02-15 15:17           ` Jeremy Linton
2013-02-15  7:17         ` Hannes Reinecke

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