linux-kernel - Re: Notes on support for multiple devices for a single filesystem

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]

Date:	Wed, 17 Dec 2008 16:30:00 -0500
From:	Jeff Garzik <jeff@...zik.org>
To:	Andreas Dilger <adilger@....com>
CC:	Chris Mason <chris.mason@...cle.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Christoph Hellwig <hch@...radead.org>, sfr@...b.auug.org.au,
	linux-kernel@...r.kernel.org, linux-btrfs@...r.kernel.org,
	linux-fsdevel@...r.kernel.org
Subject: Re: Notes on support for multiple devices for a single filesystem

Andreas Dilger wrote:
> I can't speak for btrfs, but I don't think multiple device access from
> the filesystem is a "layering violation" as some people comment.  It is
> just a different type of layering.  With ZFS there is a distinct layer
> that is handling the allocation, redundancy, and transactions (SPA, DMU)
> that is exporting an object interface, and the filesystem (ZPL, or future
> versions of Lustre) is built on top of that object interface.


Furthermore...  think about object-based storage filesystems.  They will 
need to directly issue SCSI commands to storage devices.  Call it a 
layering violation if you will, but you simply cannot even pretend that 
an OSD is a linear block device for the purposes of our existing block 
layer.

	Jeff



--
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/