On Fri, Sep 21, 2012 at 11:51 AM, Andre Robatino <robatino@xxxxxxxxxxxxxxxxx> wrote: > Renich Bon Ciric <renich <at> woralelandia.com> writes: > >> Didn't know about this. Should this be published somewhere on the >> front/download page? This is great. Thanks! > > The following issues should be noted: > > 1) In F15, the xz compression used changed, and unfortunately that isn't handled > automatically, so to use delta ISOs between versions after that, you need to > rebuild the ISOs on a machine running F15 or later. I do have semi-static > binaries in http://robatino.fedorapeople.org/deltaiso_executables/ that can be > used to rebuild recent ISOs on older OSes (F14 or below, or RHEL/CentOS, for > example), but as long as you're running F15 or later, just install the deltaiso > package from the Fedora repo and use the applydeltaiso command from that. > > 2) Since this involves delta rpms, there's the same bandwidth/CPU speed tradeoff > that's involved in deciding whether or not to use yum-presto for updates. If you > have a very fast download and a not-so-fast CPU, downloading full updated > packages becomes faster than downloading and applying delta rpms. In this case, > you could use rsync instead, which is available on at least some of the mirrors. > The yum-presto code for F18 and above will be threaded and make use of multiple > cores for rebuilding, which will make yum-presto more favorable, but the > deltaiso code isn't threaded yet (although it should be possible). > > 3) If you have the old ISO burned to optical disc, and you want to read it off > and verify the checksum before downloading the delta ISO (which is a good idea), > you need to know the exact size to read off. This is tricky. You can't just do > something like "cat /dev/sr0 > file.iso" and expect to get the right size. You > need to find the exact size, and then either use a dd command to read off > exactly that much, or use the truncate command on a padded image to reduce it to > the right size. To get the right size, you can look up the image at > http://dl.fedoraproject.org/pub/archive/ , then start a download with wget, > which shows the exact size in bytes at the beginning, then Ctrl-C it. With > standard ISOs, you would be able to look in the ISO header to find the size, but > all recent Fedora ISOs are "hybrid" which means they have extra padding in > addition to the ISO header size. Currently the extra padding consists of zeros > up to the next largest multiple of 1 MiB, so it's possible to infer the size, > but that may change in the future. I avoid all this myself by writing the exact > size of the image on my discs itself right after burning them (i.e., > "3,834,642,432 bytes" on the Fedora-17-x86_64-DVD.iso disc). Wow! Noted, thanks! ;) -- It's hard to be free... but I love to struggle. Love isn't asked for; it's just given. Respect isn't asked for; it's earned! Renich Bon Ciric http://www.woralelandia.com/ http://www.introbella.com/ -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines Have a question? Ask away: http://ask.fedoraproject.org
