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From: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
To: Fubo Chen <fubo.chen@gmail.com>
Cc: target-devel <target-devel@vger.kernel.org>,
	linux-scsi <linux-scsi@vger.kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Christoph Hellwig <hch@lst.de>, Andy Grover <agrover@redhat.com>
Subject: Re: [PATCH 10/13] iscsi-target: Add iSCSI Error Recovery Hierarchy support
Date: Thu, 28 Jul 2011 13:30:36 -0700	[thread overview]
Message-ID: <1311885036.6931.218.camel@haakon2.linux-iscsi.org> (raw)
In-Reply-To: <CAJAFBLCgOeqnrPae+GQyjnoOUkF632Nrn4Bh-3d4K3KXCezbqw@mail.gmail.com>

On Thu, 2011-07-28 at 13:42 +0200, Fubo Chen wrote:
> On Sat, Jul 23, 2011 at 10:45 AM, Nicholas A. Bellinger
> <nab@linux-iscsi.org> wrote:
> > This patch adds support for RFC-3720 compatiable ErrorRecoveryLevel
> > support as defined in Section 6.1.5.  Error Recovery Hierarchy.
> >
> > This includes support for iSCSI session reinstatement, iSCSI within
> > command and within connection recovery, and explict/implict connection
> > recovery (CSM-E and CSM-I) from state machines in Section 7 of RFC-3720.
> >
> > These functions are called from iscsi_target.c to handle processing
> > based on the negotiated session-wide ErrorRecoveryLevel parameter.
> >
> > Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
> 
> This is interesting. Is ERL2 similar to md ? If so, when should I use
> md and when ERL2 ?
> 

I think you mean dm-multipath and not md RAID here..

dm-multipath with TCM's ALUA multipath code provides a fabric
independent (iSCSI, FCoE, FC, SRP, etc) method of path failover across
multiple target ports for LUNs with a matching IEEE Extended Registered
WWN.

ERL=2 is a fabric dependent method of performing iSCSI connection
recovery on one or more failed TCP connections, where outstanding I/O
can be implictly retried and/or explictly migrated (TASK_REASSIGN) to an
active connection without having to restart the iSCSI I_T Nexus, or
notify the client side multipath layer that a I_T nexus has been lost.

Their use is not mutually exclusive, and can be used together to
complement one another.

--nab


  reply	other threads:[~2011-07-28 20:39 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-07-23  8:45 [PATCH 00/13] iscsi-target: Merge candidate for v3.1-rc1 Nicholas A. Bellinger
2011-07-23  8:45 ` [PATCH 01/13] iscsi: Resolve iscsi_proto.h naming conflicts with drivers/target/iscsi Nicholas A. Bellinger
2011-07-23 13:34   ` Jesper Juhl
2011-07-23 21:23     ` Nicholas A. Bellinger
2011-07-23  8:45 ` [PATCH 02/13] iscsi: Add Serial Number Arithmetic LT and GT into iscsi_proto.h Nicholas A. Bellinger
2011-07-23 14:25   ` Jesper Juhl
2011-07-23 21:29     ` Nicholas A. Bellinger
2011-07-23  8:45 ` [PATCH 03/13] iscsi-target: Add iSCSI fabric support for target v4.1 Nicholas A. Bellinger
2011-07-23  8:45 ` [PATCH 04/13] iscsi-target: Add target core v4.1 compatible ConfigFS control plane Nicholas A. Bellinger
2011-07-23  8:45 ` [PATCH 05/13] iscsi-target: Add ConfigFS fabric dependent statistics Nicholas A. Bellinger
2011-07-23  8:45 ` [PATCH 06/13] iscsi-target: Add TPG and device backend logic Nicholas A. Bellinger
2011-07-23  8:45 ` [PATCH 07/13] iscsi-target: Add iSCSI Login Negotiation + Parameter logic Nicholas A. Bellinger
2011-07-23  8:45 ` [PATCH 08/13] iscsi-target: Add CHAP Authentication support using libcrypto Nicholas A. Bellinger
2011-07-23 16:39   ` James Bottomley
2011-07-23 17:51     ` Linus Torvalds
2011-07-23 18:17       ` James Bottomley
2011-07-23 21:17         ` Nicholas A. Bellinger
2011-07-24  3:08           ` Mike Christie
2011-07-24  4:59             ` Nicholas A. Bellinger
     [not found]             ` <CAJAFBLCXQLvyLKR5ZD_foaPqU5X6VJfLQX_VAKeaWpDLLfPWnA@mail.gmail.com>
2011-07-24 16:32               ` Alex Couvrard
2011-07-24  3:52           ` James Bottomley
2011-07-24  4:41             ` Nicholas A. Bellinger
2011-07-24  5:50               ` James Bottomley
2011-07-24  7:52                 ` Nicholas A. Bellinger
2011-07-25 19:31               ` Andy Grover
2011-07-25 20:42                 ` Nicholas A. Bellinger
2011-07-23  8:45 ` [PATCH 09/13] iscsi-target: Add Sequence/PDU list + DataIN response logic Nicholas A. Bellinger
2011-07-23  8:45 ` [PATCH 10/13] iscsi-target: Add iSCSI Error Recovery Hierarchy support Nicholas A. Bellinger
2011-07-28 11:42   ` Fubo Chen
2011-07-28 20:30     ` Nicholas A. Bellinger [this message]
2011-07-23  8:45 ` [PATCH 11/13] iscsi-target: Add support for task management operations Nicholas A. Bellinger
2011-07-23  8:45 ` [PATCH 12/13] iscsi-target: Add misc utility logic Nicholas A. Bellinger
2011-07-28 11:30   ` Fubo Chen
2011-07-28 20:19     ` Nicholas A. Bellinger
2011-07-23  8:45 ` [PATCH 13/13] iscsi-target: Add Makefile/Kconfig and update TCM top level Nicholas A. Bellinger

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