Comment 9 for bug 578199

I've just had a look at this patch again and I see a problem.

You always offset by 63 sectors, despite the out of ubuntu-vmbuilder saying (see attached output) that the CHS geometry used was */4/32. You are offsetting by 63 sectors, so that's not a a cyl boundary.

More seriously, if this image goes via iSCSI, you ENSURE no read is 4k aligned, which is very bad performance wise.

I suggest offsetting by 64 cylinders, not 63.

Alex

sfdisk -l -uS ./ubuntu-lucid-amd64-httpmetadata.img
Disk ./ubuntu-lucid-amd64-httpmetadata.img: cannot get geometry

Disk ./ubuntu-lucid-amd64-httpmetadata.img: 2610 cylinders, 255 heads, 63 sectors/track
Warning: The partition table looks like it was made
  for C/H/S=*/4/32 (instead of 2610/255/63).
For this listing I'll assume that geometry.
Units = sectors of 512 bytes, counting from 0

   Device Boot Start End #sectors Id System
./ubuntu-lucid-amd64-httpmetadata.img1 1 39996093 39996093 83 Linux
./ubuntu-lucid-amd64-httpmetadata.img2 0 - 0 0 Empty
./ubuntu-lucid-amd64-httpmetadata.img3 0 - 0 0 Empty
./ubuntu-lucid-amd64-httpmetadata.img4 0 - 0 0 Empty