Re: [dm-devel] Re: [RFC][PATCH] dm-cache: block level disk cache target for device mapper

[Ming Zhang <blackmagic02881@gmail.com>]

On Mon, 2006-11-27 at 13:55 -0600, Eric Van Hensbergen wrote:
> On 11/27/06, bert hubert <bert.hubert@netherlabs.nl> wrote:
> > On Mon, Nov 27, 2006 at 06:26:34PM +0000, Eric Van Hensbergen wrote:
> > > This is the first cut of a device-mapper target which provides a write-back
> > > or write-through block cache.  It is intended to be used in conjunction with
> > > remote block devices such as iSCSI or ATA-over-Ethernet, particularly in
> > > cluster situations.
> >
> > How does this work in practice? In other words, what is a typical actual
> > configuration?
> >
> > There is a remote block device, and a local one, and these are kept into
> > sync in some way?
> >
> 
> That's the basic idea.  In our testbed, we had a single iSCSI server
> exporting block devices to several clients -- each maintaining their
> own local disk cache of the server exported block devices.  You can
> configured either write-through or write-back policies -- write-back
> has better performance, but somewhat obvious consistency issues in
> failure cases.
> 
> The original intent was to combine this with the dm-cow target (which
> I posted a few hours before the dm-cache patch) to provide a scalable
> cluster deployment system based on back-end iSCSI or ATA-over-Ethernet
> storage.

like to see this idea but any similarity with
http://www.ele.uri.edu/Research/hpcl/STICS/stics.pdf?

STICS is patent pending so not sure if kernel can be free to merge this
dm-cache.


> 
>           -eric
> 
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