On Wed, 2012-03-21 at 14:32 +0100, Jan Safranek wrote: > On 03/21/2012 02:18 PM, David Lehman wrote: > > On Wed, 2012-03-21 at 13:55 +0100, Jan Safranek wrote: > >> > >> start: 110592 end: 112454 length: 1863 > >> This is a free space between two logical partitions. > >> -> Again, why is the free region here? And there are 186 'hidden' > >> sectors between this free space end and start of the next logical partition. > > > > We are somewhat more liberal with rounding start sector up for logical > > partitions, basically because parted is more aggressive in aligning > > start of logical partitions than it is with normal partitions. Also, we > > need to account for at least one sector of metadata before each logical > > partition. In some unfortunate cases this bump to the next MB boundary > > can amount to 2047 520-byte sectors. Again, parted is so aggressive with > > this that we had to do the same in order to ensure that parted > > magic/fixups do not cause unwanted surprises when the partitions are > > added to disk. > > Please correct me if I am wrong - I understand it as the logical > partition metadata is at sector 112455 (=end of the free space > before+1), then there are 185 unused sectors because of alignment and > the usable data on a partition starts at sector 112640, as reported by > fdisk and storage.partitions. Nothing can ever touch these 186 sectors, > because it might overwrite the metadata. Correct. > > >> If the alignment to cylinder boundary is cause of these weird numbers, > >> can I turn the alignment off in pyanaconda.storage? The numbers > >> reported by disks are completely artificial anyway these days. > > > > We turn off cylinder alignment already. > > What alignment is used then? Why the partitions don't follow each other? The kernel has specified that partitions on that disk should always start on a 2048-sector boundary. Aligning up from sector 1 or 63 gets you to sector 2048. Likewise, the rest of the start sectors will all be multiples of 2048. > > Jan > > >> /dev/sda6 90112 110591 10240 83 Linux > >> /dev/sda7 112640 133119 10240 83 Linux > > _______________________________________________ > Anaconda-devel-list mailing list > Anaconda-devel-list@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/anaconda-devel-list _______________________________________________ Anaconda-devel-list mailing list Anaconda-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/anaconda-devel-list
