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From: Robert Watson <rwatson@FreeBSD.org>
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To: Alexander Motin <mav@FreeBSD.org>
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Cc: svn-src-projects@freebsd.org, src-committers@freebsd.org,
	Pawel Jakub Dawidek <pjd@FreeBSD.org>, John Baldwin <jhb@freebsd.org>
Subject: Re: svn commit: r217828 - projects/graid/head/sys/geom/raid
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On Wed, 26 Jan 2011, Alexander Motin wrote:

> That's all true. Those who want maximum robustness should use dedicated 
> drive on the most trivial dedicated controller to make dumping reliable. If 
> we are going above that - there are always some compromises.

This seems to be the best conclusion in the NIC space certainly -- for network 
debugging and crashdumps, a dedicated NIC involves far fewer compromises. 
However, the traditional route of resetting $controller when you realise 
you're past the point of no return, and then doing polled I/O to the freshly 
initialised device, should be pretty reliable under most circumstances.

> What's about dumping to GEOM, I think that with r217827 change (in 
> projects/graid/head) it should be possible to implement robust dumping to 
> gmirror and gstripe without doing any allocations and GEOM interaction. With 
> some efforts it could also be done to graid by writing specialized 
> minimalistic dumping routines for every transformation module (at least it 
> seems trivial for RAID0/RAID1).

Sounds good.

Robert