[CentOS] 4kB sector size HDDs

Thu Apr 21 15:17:48 UTC 2011
Devin Reade <gdr at gno.org>

--On Thursday, April 21, 2011 11:16:36 AM +0200 Dawid Horacio Golebiewski
<dawid.golebiewski at tu-harburg.de> wrote:

> Do any of you have one of the 'new' HDDs with 4kB Sectors currently in
> use?

I have them in use, and set up the partitions manually before installing
the OS.  This is the relevent entry from my server changelog, prior to
installing CentOS 5.5:

    + since this machine is using new drives with 4k blocks,
      used fdisk to ensure that sector alignment will be sane:

        fdisk -H 224 -S 56 /dev/sd{a,b} 

      In doing so, I created a 200MB RAID1 partition (type 0xfd)
      and another RAID1 partition with the remaining disk for use
      by LVM.

      I found it necessary to use fdisk manually on both disks,
      because the following command choked (probably due to
      the geometry thing):

        sfdisk -d /dev/sda | sfdisk /dev/sdb
        (DOESN'T WORK)

I case it's not obvious, the partitions on sda and sdb are then
mirrored, the small one for /boot, the large one for the remaining
filesystems under LVM.

If you're using the Caviar green drives, beware of excessive head
park and quickly increasing load cycle counts.  I fixed that with
using an idle timeout of 300 seconds (vice 8 seconds) per: