From: Hannes Reinecke <hare@suse.de>
To: Bart Van Assche <bart.vanassche@gmail.com>
Cc: "Ewan D. Milne" <emilne@redhat.com>, linux-scsi@vger.kernel.org
Subject: Re: [PATCH RFC 0/9] [SCSI] Enhanced sense and Unit Attention handling
Date: Thu, 24 Jan 2013 15:51:39 +0100 [thread overview]
Message-ID: <51014A7B.2060806@suse.de> (raw)
In-Reply-To: <CAO+b5-ptjPEbCrKEpdCEZBCh5Xs7ycXQA5V+iohAL4TSfbUzFg@mail.gmail.com>
On 01/24/2013 03:38 PM, Bart Van Assche wrote:
> On Thu, Jan 24, 2013 at 4:38 AM, Hannes Reinecke <hare@suse.de> wrote:
>> As for AEN, does iSCSI _do_ AEN? I thought it got removed ...
>>
>> If it does, though, it should schedule an event on its own whenever an AER
>> is received. The same goes for LLDDs with vendor-specific AENs; thinking of
>> megaraid_sas here ...
>
> Let me ask this another way. SAN users expect that the LUN list at the
> initiator side gets updated automatically after a SAN configuration
> change. How should a SAN system communicate to a SCSI initiator that
> the LUN list has been changed ? Some FC SAN systems send a LIP after a
> configuration change to force the initiator to rescan LUNs.
And thereby disrupting traffic on _ALL_ LUNs on the loop.
Really cool idea.
I know; the one vendor which does _not_ talk to us.
> But how to inform the initiator about a LUN change for other SCSI protocols ?
> I'm not sure that it is even possible to report such a change via
sense
> data in case a SAN user first removes all LUNs and after that change
> adds one or more LUNs.
>
The official way is indeed via UAs; most storage arrays (Hello,
NetApp!) provide a default LUN0 which is always visible.
Up to the point that some even refuse to add 'normal' disk LUNs to
LUN0. Or have the ominous 'Well-known Address' LUN to handle these
kind of issues.
Obviously, one needs to send commands to it to even _get_ an UA back.
But yeah, normally it's possible.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@suse.de +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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next prev parent reply other threads:[~2013-01-24 14:51 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-18 16:27 [PATCH RFC 0/9] [SCSI] Enhanced sense and Unit Attention handling Ewan D. Milne
2013-01-18 16:27 ` [PATCH RFC 1/9] [SCSI] Detect overflow of sense data buffer Ewan D. Milne
2013-01-18 16:46 ` James Bottomley
2013-01-21 7:26 ` Hannes Reinecke
2013-01-21 8:58 ` James Bottomley
2013-01-21 17:42 ` Douglas Gilbert
2013-01-22 15:10 ` Ewan Milne
2013-01-23 7:16 ` Hannes Reinecke
2013-01-22 15:08 ` Ewan Milne
2013-01-23 10:44 ` Hannes Reinecke
2013-01-23 13:06 ` James Bottomley
2013-01-23 21:21 ` Ewan Milne
2013-01-18 16:27 ` [PATCH RFC 2/9] [SCSI] Generate uevent on sd capacity change Ewan D. Milne
2013-01-18 16:27 ` [PATCH RFC 3/9] [SCSI] Add a kernel config option for enhanced Unit Attention support Ewan D. Milne
2013-01-18 16:27 ` [PATCH RFC 4/9] [SCSI] Rename scsi_evt_xxx to sdev_evt_xxx and scsi_event to sdev_event Ewan D. Milne
2013-01-22 17:33 ` Bart Van Assche
2013-01-23 21:08 ` Ewan Milne
2013-01-22 17:38 ` Bart Van Assche
2013-01-23 20:39 ` Ewan Milne
2013-01-18 16:27 ` [PATCH RFC 5/9] [SCSI] Add support for scsi_target events Ewan D. Milne
2013-01-18 16:27 ` [PATCH RFC 6/9] [SCSI] Generate uevents for certain Unit Attention codes Ewan D. Milne
2013-01-18 16:27 ` [PATCH RFC 7/9] [SCSI] Add sysfs support for enhanced Unit Attention handling Ewan D. Milne
2013-01-18 16:27 ` [PATCH RFC 8/9] [SCSI] Add sense and Unit Attention generation to scsi_debug Ewan D. Milne
2013-01-19 18:43 ` Douglas Gilbert
2013-01-22 15:12 ` Ewan Milne
2013-01-18 16:27 ` [PATCH RFC 9/9] [SCSI] Streamline detection of FM/EOM/ILI status Ewan D. Milne
2013-01-24 0:19 ` [PATCH RFC 0/9] [SCSI] Enhanced sense and Unit Attention handling Bart Van Assche
2013-01-24 11:38 ` Hannes Reinecke
2013-01-24 14:00 ` Ewan Milne
2013-01-24 14:01 ` Mike Christie
2013-01-24 22:02 ` Ewan Milne
2013-01-24 22:47 ` Mike Christie
2013-01-24 14:38 ` Bart Van Assche
2013-01-24 14:51 ` Hannes Reinecke [this message]
2013-01-24 15:00 ` Mike Christie
2013-01-24 15:15 ` Hannes Reinecke
2013-01-24 22:00 ` Ewan Milne
2013-01-26 18:20 ` Mike Christie
2013-01-28 6:56 ` Hannes Reinecke
2013-01-28 15:05 ` Jeremy Linton
2013-01-28 15:44 ` Bart Van Assche
2013-01-28 15:48 ` Hannes Reinecke
2013-01-28 20:26 ` James Bottomley
2013-01-28 15:52 ` Jeremy Linton
2013-01-28 16:04 ` Ewan Milne
2013-01-28 16:18 ` Mike Christie
2013-01-29 5:01 ` Shyam_Iyer
2013-01-24 13:53 ` Ewan Milne
2013-01-31 16:27 ` Ewan Milne
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