Rsync: Re: patch to enable faster mirroring of large filesyst ems

[Keating, Tim]

In my particular case, it is reasonable to assume that the size and
timestamp will change when the file is updated. (We are looking at it as a
patching mechanism.)

Right now it's actually using update time only, I should modify it to check
the file size as well.

Is there a way you could query your database to tell you which extents have
data that has been modified within a certain timeframe?

> -----Original Message-----
> From: David Bolen [mailto:db3l at fitlinxx.com]
> Sent: Thursday, November 29, 2001 2:12 PM
> To: 'Keating, Tim'
> Cc: rsync at samba.org
> Subject: RE: Rsync: Re: patch to enable faster mirroring of large
> filesyst ems 
> 
> 
> Keating, Tim [TKeating at origin.ea.com] writes:
> 
> >  - If there's a mismatch, the client sends over the entire .checksum
> > file.  The server does the compare and sends back a list of files to
> > delete and a list of files to update. (And now I think of it, it
> > would probably be better if the server just sent the client back the
> > list of files and let the client figure out what it needed, since
> > this would distribute the work better.)
> 
> Whenever caching checksums comes up I'm always curious - how do you
> figure out if your checksum cache is still valid (e.g., properly
> associated with its file) without re-checksumming the files?
> 
> Are you just trusting size/timestamp?  I know in my case I've got
> database files that don't change timestamp/size and yet have different
> contents.  Thus I'd always have to do full checksums so I'm not sure
> what a cache would buy.
> 
> -- David
> 
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