[clue-tech] Mirroring Debian testing, i386.

[David L. Anselmi]

Keith Hellman wrote:
> On Mon, Dec 24, 2007 at 12:58:56PM -0700, David L. Anselmi wrote:
[...]
>> So its overhead for checking for changes is wasted.
> 
> This isn't my experience (I use rsync for all my backup scripts).
> Granted, I probably don't do the volume of bits or inodes in a debian
> repo.
 >
> If what you say is true, then the -I option to rsync doesn't make much
> sense, and I wonder why it is provided:
>  -I, --ignore-times
>    Normally rsync will skip any files that are already the same size and
>    have the same  modification time-stamp.   This option turns off this
>    "quick check" behavior, causing all files to be updated.

I didn't mean that the overhead is large.  But it checks time stamps 
across the network on over 21k files.  That may be required on for 
backups but not for mirroring (in this case anyway).

apt-mirror downloads the new Packages file and checks the size of all 
the files listed there against what's on disk.  I think it's impossible 
for a debian package to change and keep the same size and name (which 
includes the version number).

So you get the Packages files, which you need anyway, and the rest is 
local.  Not so general a solution as rsync but I'm happy to have a much 
quicker estimate of how much needs to be updated.

I guess there's no magic to it.  If the "local" mirror were an NFS mount 
on a 1Mbps link it'd be the same as rsync.

Good to hear from you though.

Dave