On 2010-08-10, at 3:01 AM, Karel Zak wrote: > On Mon, Aug 09, 2010 at 09:00:35PM -0400, Eric Thibodeau wrote: >> As per ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/v2.18/v2.18-ReleaseNotes : >> >> fdisk(8): >> - supports new command line option "-c" to switch off DOS mode >> - uses 1MiB offset for the first partition >> (all these changes are already in the release 2.17.2) >> >> I presume the 1MiB offset is to accomodate for grub2. > > No, the offset (and alignment to MiBs) is there for compatibility and > portability (raids, 4K sector disks, win7, ...). OK, I was biased in that train of thoughts. Nonetheless, this offset would probably make life easier for anyone (like me) wanting to use sfdisk + grub2, which requires a larger post-MBR gap than in the past. Could it also be added to sfdisk as an option? >> My attempts in partitioning a drive with a 1MiB post-MBR gap failed > > sfdisk has tendency to use CHS to calculate partition size, it means > that 1MiB does not have to be on cylinder boundary. You have to use > sectors as basic units. > > The another problem is that it checks against cylinder boundary, so > you need to use --force ... > >> with the following command line call: >> >> sfdisk -uM -L /dev/sda <<-EOF > > try to use -uS, it seems that sfdisk rounds to cylinders if magabyte > is specified (this should be fixed). > >> 1,256,fd >> ,512,fd >> ,,fd >> ; >> EOF > > for example: > > sfdisk --force -uS /dev/sdb <<EOF > 2048 102400 0x83 > 104448 1206272 0x83 > EOF > > result: > > sfdisk -uS -l /dev/sdb > > Device Boot Start End #sectors Id System > /dev/sdb1 2048 104447 102400 83 Linux > /dev/sdb2 104448 1310719 1206272 83 Linux > > > My suggestion is to use fdisk rather than sfdisk, if you really need > create partitions from script than is probably the best way to to > create the partitions by fdisk and then dump the layout by > > sfdisk -uS -d <dev> > part.txt > > and then call from scripts > > sfdisk <dev> < part.txt > > or use the latest versions of GNU Parted. Well, that is my next step, my intention was to script this into a copy-pastable format. I'll look more seriously into parted then. Thanks. > Karel > > -- > Karel Zak <kzak@xxxxxxxxxx> > http://karelzak.blogspot.com -- To unsubscribe from this list: send the line "unsubscribe util-linux-ng" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
