Re: Accessing the same disk via multiple channels

From: Lars Marowsky-Bree (lmb@suse.de)
Date: Mon Feb 17 2003 - 04:52:15 EST


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-Brée <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
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Sun Feb 23 2003 - 22:00:17 EST