On 05/21/2010 04:32 PM, Les Mikesell wrote:
> On 5/21/2010 4:19 PM, John R Pierce wrote:
>> Les Mikesell wrote:
>>> But it is just a match for the Seagate drives with the default layout
>>> using one partition that fills the disk. If I have to skip some amount
>>> at the start of the partition I think that will make the partition size
>>> not match, making it impossible to add as a raid member.
>>>
>>
>> 750GB drives can vary quite a bit in size +/- depending on the exact
>> model. The required trim is 0-3.5K, and its due to the MBR on the
>> first "track" of the drive before the first/primary partition starts.
>
> The 3.5" Seagates look like:
> Disk /dev/sdc: 750.1 GB, 750156374016 bytes
> 255 heads, 63 sectors/track, 91201 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
>
> Device Boot Start End Blocks Id System
> /dev/sdc1 1 91201 732572001 fd Linux raid autodetect
>
> And the 2.5 WD looks the same to me:
>
> Disk /dev/sdh: 750.1 GB, 750156374016 bytes
> 255 heads, 63 sectors/track, 91201 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
>
> Device Boot Start End Blocks Id System
> /dev/sdh1 1 91201 732572001 fd Linux raid autodetect
You have another way out. By my calculation, that drive is partitioned
in DOS compatibility mode, which leaves the remainder of the MBR track
unused. Running fdisk in expert mode ("x" command), you can move the
partition's beginning of data ("b" command) from sector 63 back to
sector 56. That will give you the needed 4K alignment and a partition
that is no smaller than what it was before.
--
Bob Nichols "NOSPAM" is really part of my email address.
Do NOT delete it.