[CentOS] ext4, 4k sector alignment

Robert Nichols rnicholsNOSPAM at comcast.net
Wed Jul 27 00:57:11 UTC 2011


On 07/26/2011 03:53 PM, Les Mikesell wrote:
> Thank you!  That seems to have worked, but now I'm curious as to why the
> partition on the old drives didn't go to the end of the disk - which I
> had expected would have left no extra room.  Was the dos style rounding
> computing the end of a cylinder wrong?
>
> fdisk -lu /dev/sdh (old 3.5")
> Disk /dev/sdh: 750.1 GB, 750156374016 bytes
> 255 heads, 63 sectors/track, 91201 cylinders, total 1465149168 sectors
> Units = sectors of 1 * 512 = 512 bytes
> Device Boot   Start         End      Blocks   Id  System
> /dev/sdh1       63  1465144064   732572001   fd  Linux raid autodetect

Simple.  The drive does not contain an integral number of those arbitrary
255H x 63S cylinders, and with the previous cylinder-aligned partitioning
the partition extended only to the end of the last full cylinder.

-- 
Bob Nichols     "NOSPAM" is really part of my email address.
                 Do NOT delete it.




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