Dnia 2014-01-17, o godz. 10:18:58 Alec Warner <anta...@gentoo.org> napisał(a):
> On Fri, Jan 17, 2014 at 8:27 AM, Michał Górny <mgo...@gentoo.org> wrote: > > > Hello, all. > > > > I'm using squashfs to hold my Gentoo repositories on all of my systems > > for some time. As you probably know, this allows me to save space while > > keeping portage fast. However, it makes updating the tree quite > > burdensome and time-consuming. > > > > We're already hosting daily gx86 tarballs on our mirrors, and deltas > > made using diffball. Those can be used with Zac's emerge-delta-webrsync > > to get daily updates done with minimal network overhead. Sadly, it > > takes the whole process even more time consuming :). > > > > Therefore, I'd like to suggest an alternative solution that could help > > out Gentoo users that use squashfs for gx86 and would like to be able > > to get daily updates fast and easy. > > > > The idea is to host -- along with the tarballs -- daily squashfs images > > of gx86 in a chosen format. Additionally, the images would come with > > deltas made using xdelta3 or a similar tool. Those deltas -- with > > a slight download overhead -- would allow very fast updates > > of the squashfs. > > > > Now some numbers. I did some tests 'converting' late gx86 daily > > tarballs to squashfs. I've used squashfs 4.2 with LZO compression > > since it's quite good and very fast. > > > > 96M portage-20140108.sqfs > > 96M portage-20140109.sqfs > > 96M portage-20140110.sqfs > > 96M portage-20140111.sqfs > > 96M portage-20140112.sqfs > > 96M portage-20140113.sqfs > > 97M portage-20140114.sqfs > > 97M portage-20140115.sqfs > > > > For deltas, I've used xdelta3 with max compression (-9) and djw > > secondary compression (it gave ~0.1M smaller files than fgk > > and ~0.5M gain than with no secondary compression). > > > > 4,9M portage-20140108.sqfs-portage-20140109.sqfs.vcdiff.djw > > 6,3M portage-20140109.sqfs-portage-20140110.sqfs.vcdiff.djw > > 5,6M portage-20140110.sqfs-portage-20140111.sqfs.vcdiff.djw > > 8,9M portage-20140111.sqfs-portage-20140112.sqfs.vcdiff.djw > > 6,3M portage-20140112.sqfs-portage-20140113.sqfs.vcdiff.djw > > 7,8M portage-20140113.sqfs-portage-20140114.sqfs.vcdiff.djw > > 8,5M portage-20140114.sqfs-portage-20140115.sqfs.vcdiff.djw > > > > As you can see, the deltas are quite large compared to the actual > > changes. However, we could have expected that since we're diffing > > a compressed filesystem. What's important, however, is that applying > > it takes ~2.5 second on my 2 GHz Athlon64. > > > > It wasn't clear to me, are these trees with metadata included? Yes, full metadata with md5-cache. That's the same thing you get via 'emerge --sync'. And that's why the deltas are so big -- I recall three big cache updates this week. -- Best regards, Michał Górny
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