Re: What are .commitmeta files and why is delta update so huge?

[Leandro Santiago <leandrosansilva gmail com>]

On 25 June 2015 at 18:07, Giuseppe Scrivano <gscrivano gnu org> wrote:
> Leandro Santiago <leandrosansilva gmail com> writes:
>
> > Well, they are quite small (a few kb). Is there any tool to analyse
> > the content of those files? (I bet not, but asking does not hurt :-))
> >
> > There might be some other changes, as I create a new tree from the
> > scratch using rpm-ostree tree compose. But the files are supposed to
> > be almost the same, as I am using centos and I don't think so many
> > updates were made in so short interval of time (I built the two trees
> > with a short interval between them).
> >
> > I'll try what you suggested, even though I am not sure if it will help
> > as what I need is reducing the amount of downloaded data.
>
> it might help since only the difference between the two files is going
> to be stored in the delta file, instead of downloading the entire new
> file blob.
>
> Another thing you can try to check if OStree is doing the right thing is:
>
> ostree --repo=repo diff --fs-diff --stats $COMMIT_ID_1 $COMMIT_ID_2
This command is amazing :-) By using it I realized there were a more
changes involving big files.
Files which haven't changed indeed, but just renamed during the tree
creation by ostree. This is the important part of the diff:
D    
/boot/initramfs-3.10.0-229.7.2.el7.x86_64.img-c8c66111612920826e08d9b10a09624be3d41cedb44ea9cc40afe7b0cc74f124
D    /boot/vmlinuz-3.10.0-229.7.2.el7.x86_64-c8c66111612920826e08d9b10a09624be3d41cedb44ea9cc40afe7b0cc74f124
D    
/usr/lib/ostree-boot/initramfs-3.10.0-229.7.2.el7.x86_64.img-c8c66111612920826e08d9b10a09624be3d41cedb44ea9cc40afe7b0cc74f124
D    
/usr/lib/ostree-boot/vmlinuz-3.10.0-229.7.2.el7.x86_64-c8c66111612920826e08d9b10a09624be3d41cedb44ea9cc40afe7b0cc74f124
A    
/boot/initramfs-3.10.0-229.7.2.el7.x86_64.img-755d6f3609c093448a21efdadb8ef173f26d596eec6ad8194f83f20566618ba3
A    /boot/vmlinuz-3.10.0-229.7.2.el7.x86_64-755d6f3609c093448a21efdadb8ef173f26d596eec6ad8194f83f20566618ba3
A    
/usr/lib/ostree-boot/initramfs-3.10.0-229.7.2.el7.x86_64.img-755d6f3609c093448a21efdadb8ef173f26d596eec6ad8194f83f20566618ba3
A    
/usr/lib/ostree-boot/vmlinuz-3.10.0-229.7.2.el7.x86_64-755d6f3609c093448a21efdadb8ef173f26d596eec6ad8194f83f20566618ba3

It means on each time rpm-ostree renames the files vmlinuz and
initramfs, it creates different names, so the files are considered
different, even though having the same content. As those files are
big, the diff is also big. I guess this is a bug on rpm-ostree (my
system is based on centos7), isn't it? It should preferably use same
filename for them all keeping the diff small IMHO.

Thanks a lot for your help :-)

> and check what files are changed.
>
> Regards,
> Giuseppe



-- 
Sent from my mind