linux-kernel - Re: [RFD] Layering: Use-Case Composers (was: DRBD - what is it, anyways? [compare with e.g. NBD + MD raid])

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <46C01052.4050708@dgreaves.com>
Date:	Mon, 13 Aug 2007 09:03:30 +0100
From:	David Greaves <david@...eaves.com>
To:	david@...g.hm
Cc:	Paul Clements <paul.clements@...eleye.com>,
	Jan Engelhardt <jengelh@...putergmbh.de>,
	Al Boldi <a1426z@...ab.com>, linux-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org, netdev@...r.kernel.org,
	linux-raid@...r.kernel.org
Subject: Re: [RFD] Layering: Use-Case Composers (was: DRBD - what is it, anyways?
 [compare with e.g. NBD + MD raid])

david@...g.hm wrote:
> per the message below MD (or DM) would need to be modified to work 
> reasonably well with one of the disk components being over an unreliable 
> link (like a network link)
> 
> are the MD/DM maintainers interested in extending their code in this 
> direction? or would they prefer to keep it simpler by being able to 
> continue to assume that the raid components are connected over a highly 
> reliable connection?
> 
> if they are interested in adding (and maintaining) this functionality 
> then there is a real possibility that NBD+MD/DM could eliminate the need 
> for DRDB. however if they are not interested in adding all the code to 
> deal with the network type issues, then the argument that DRDB should 
> not be merged becouse you can do the same thing with MD/DM + NBD is 
> invalid and can be dropped/ignored
> 
> David Lang

As a user I'd like to see md/nbd be extended to cope with unreliable links.
I think md could be better in handling link exceptions. My unreliable memory 
recalls sporadic issues with hot-plug leaving md hanging and certain lower level 
errors (or even very high latency) causing unsatisfactory behaviour in what is 
supposed to be a fault 'tolerant' subsystem.


Would this just be relevant to network devices or would it improve support for 
jostled usb and sata hot-plugging I wonder?

David

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