[gentoo-dev] Re: RFC: Hosting daily gx86 squashfs images and deltas

[Duncan]

Michał Górny posted on Fri, 17 Jan 2014 20:30:00 +0100 as excerpted:

> Dnia 2014-01-17, o godz. 19:19:14 Duncan <1i5t5.duncan@×××.net>
> napisał(a):
>
>> Michał Górny posted on Fri, 17 Jan 2014 17:27:30 +0100 as excerpted:
>>
>> > 96M	portage-20140108.sqfs

>> > For deltas [...]
>> >
>> > 6,3M portage-20140109.sqfs-portage-20140110.sqfs.vcdiff.djw

>> > applying it takes ~2.5 second on my 2 GHz Athlon64.
>>
>> diffs are ~1/16 the full squashfs size[.] So people updating once a
>> week [or] 10 days would see a bandwidth savings, provided the sync
>> script was intelligent enough to apply updates serially.
>>
>> The breakover point would be roughly an update every two weeks, or
>> twice a month
>
> However, it may be actually beneficial to provide other durations, like
> weekly deltas. In my tests, the daily updates for this week summed up to
> almost 50M while the weekly was barely 20M.

That's useful additional data.  Thanks.

And yes, a weekly delta would be quite useful, taking the breakover point 
out to about a month or so.  Practically speaking, I'd guess most 
gentooers update once a month or more, so that should cover the vast 
majority.  Beyond a month, just downloading a new full squashfs makes as 
much sense anyway, and as the cutover would be automated, users on the 
borderline wouldn't have to worry about whether they should just do the 
normal sync or download an entirely new tarball, as they now need to do, 
if they even bother at all.  For those users, it'd be an even BIGGER win.

=:^)

-- 
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