On 04/13/2013 03:54 AM, Akemi Yagi wrote:
> On Thu, Apr 11, 2013 at 10:57 AM, Steven Haigh <[log in to unmask]> wrote:
>> Hi all,
>>
>> I'm wondering why we don't take advantage of deltarpms for updates on SL6
>> (and maybe SL5).
>>
>> There are a few people I know that bandwidth is an issue - and something
>> like this would solve that problem.
>>
>> I do know its a bit more work, but it is something that can easily be
>> automated...
>
> I think that maintaining deltarpms involves more than 'a bit more
> work'.  Take a look, for example, at CentOS's drpms directory:
>
> http://mirror.centos.org/centos/6/updates/x86_64/drpms/
>
> The total size of this directory as of this writing is 7.6 GB. For
> comparison, the corresponding Packages/ directory is 0.49 GB. This
> means two things. One is that not just the SL sites but all mirror
> sites would see the increase in the volume. The other is that building
> the drpm packages will take a significant amount of time. And this
> must be done for *each* package update. This is potentially a resource
> hog.

Yeah - CentOS creates deltas for the last 7 versions of packages. I'd 
usually say 3 is good, 5 is great (however not required). It really 
makes sense to only enable deltas for sl6x-security, sl6x-fastbugs. I 
guess you COULD also do it on the main sl6x repo to greatly reduce the 
bandwidth required to update between major point releases...

Just as a quick example... Upgrading bind from the base to the latest in 
updates is:
bind-9.8.2-0.17.rc1.el6_4.4.x86_64.rpm - 4Mb

Using the delta, this reduces to about 450Kb.

I recently installed Fedora 18 on a netbook - the initial update from 
the install DVD to be in sync with all the updates was reduced by over 
60% by using deltas. The lower bandwidth required to transfer this is 
significant.

I don't see it being a resource hog - as just like creating the packages 
in the first place, you do it once, and its done. It is also managed 
automatically by createrepo.

> So, the question will be whether or not the requirement for more
> resources can be justified by the demand for drpms. At least in the
> past, most SL users were associated with universities or research
> institute where the bandwidth was not a primary issue. Besides, many
> of those sites probably maintain their local mirror.

I agree, universities probably get the better end of the stick in the 
US. Don't confuse this with the rest of the world though :)

There are quite a few universities around the globe that charge their 
students for internet access - and lots of people around the globe that 
*still* cannot get more than dialup internet access. I agree that in the 
past, universities were probably the biggest user of SL - these days I 
would say that casual users would greatly outnumber university users.

Recently on the #slforum channel on freenode I have been talking to an 
SL user that is stuck on SL5.5 - as to download the 6.4 ISO would take 
almost a week. This obviously started the chain of thought regarding 
deltas...

-- 
Steven Haigh

Email: [log in to unmask]
Web: https://www.crc.id.au
Phone: (03) 9001 6090 - 0412 935 897
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