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Date: Mon, 17 Feb 2003 10:52:15 +0100
From: Lars Marowsky-Bree <lmb@suse.de>
To: Patrick Mansfield <patmans@us.ibm.com>, linux-kernel@vger.kernel.org
Subject: Re: Accessing the same disk via multiple channels
Message-ID: <20030217095215.GF9034@marowsky-bree.de>
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On 2003-02-14T15:37:47,
   Patrick Mansfield <patmans@us.ibm.com> said:

> Generic multi-path without the lower levels knowing anything can waste a
> lot of resources. For example, for each extra path to a block device
> (disk) we end up with an extra sd plus associated data structures, and an
> extra scsi_device including multiple request queues.

I think these somehow still need to be exposed so that userspace can do
per-path diagnostics; unless you also want to move this into the kernel space,
which I'm not sure about.

What we really need is better error handling and escalation so that a higher
layer actually has a chance at really well done recovery and retrying.


Sincerely,
    Lars Marowsky-Br?e <lmb@suse.de>

-- 
Principal Squirrel 
SuSE Labs - Research & Development, SuSE Linux AG
  
"If anything can go wrong, it will." "Chance favors the prepared (mind)."
  -- Capt. Edward A. Murphy            -- Louis Pasteur
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