Cylinders are largely logical - even in magnetic disks you have no way of knowing if the logical cylinder matches up with the physical construct of a cylinder on the disk medium - in any modern(15 years ?) disk they won't. Don't worry about cylinders, just align your fs to the stripe/sector.
Obviously, the concept of a cylinder starts to go out the window with RAID, SSD's, etc. More information about partition alignment here - http://www.ocztechnologyforum.com/forum/showpost.php?p=335049&postcount=134 --Blake -------- Original Message -------- Subject: [CentOS] Stripe vs Cylinder alignement... From: John Doe <jd...@yahoo.com> To: centos@centos.org Date: Friday, October 30, 2009 9:45:59 AM > Hi, > > I modified my kickstart to do some custom partioning and formating in a > pre-install script. > I am trying to align the partitions on the RAID stripe (and format with a > correct stride). > But, sfdisk complains that it does not start/end on a cylinder boundary (used > -L option to limit complaining). > Since the cylinder size is not a multiple of the stripe size, I cannot align > on both. > I tried to align the begining on the stripe and the end on the end of a > cylinder, but sfdisk still compains... > Basicaly, I have a 128KB (256 sectors) stripe, and 255*32 = 8160 sectors > cylinders. > What I am doing is: > begin = ( begin / 256 ) * 256 > end = ( end / 8160 ) * 8160 -1 > So, for my first partition (96MB): > begin=256 > size = ( ( 96 * 1024 * 2 ) / 8160 ) * 8160 = 195840 sectors > end = 195840 - 1 - 256 = 195583 > Any idea what I am doing wrong in my calculations or logic? > > Thx, > JD > > > > _______________________________________________ > CentOS mailing list > CentOS@centos.org > http://lists.centos.org/mailman/listinfo/centos > _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
