RE: [Xen-users] loopback domU write

["Petersson, Mats" <Mats.Petersson@xxxxxxx>]

> -----Original Message-----
> From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx 
> [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of 
> Chris Moore
> Sent: 08 June 2007 20:18
> To: xen-users@xxxxxxxxxxxxxxxxxxx
> Subject: [Xen-users] loopback domU write
> 
> 
> I have a architecture-esque question:
> 
> When a file-backed(loopback, not blktap) PV domU writes, I 
> have heard that it does not write directly to disk and is 
> buffered somewhere.
> Where then, is it buffered?  Is it in the dom0 loopback 
> driver(mem), the dom0 filesystem cache(mem) or somewhere else? 

The dom0 filesystem cache will DEFINITELY be a part of the
caching/buffering. I don't know if the loopback driver also has some
caches - it seems silly to cache here (because it is better to have one
(larger) cache in one place (compared to multiple smaller caches), and
loopback ends up in a filesystem driver sooner or later), but it's
obviously POSSIBLE to do. 

--
Mats
> 
> Thanks
> Chris
> 
> 
> 



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