Re: [gentoo-user] Partition of 3TB USB drive not detected

[james <garftd@verizon.net>]

On 08/06/2016 02:21 AM, Andrea Conti wrote:
> Hi,
>
>> ~ # parted /dev/sde print
>> Model: WD My Book 1230 (scsi)
>> Disk /dev/sde: 6001GB
>> Sector size (logical/physical): 4096B/4096B
>
> [...]
>
>> AFAICS this partition works fine, fsck does not report any problem. The
>> funny thing is, it should not have been possible, because of the 2GB limit
>> of MBR.
>
> The real limit of MBR is 2^32 sectors, which amounts to 2TB when using
> 512B sectors. Both your disks are using native 4kB sectors (look at the
> logical sector size in the parted output), which effectively raises the
> MBR limit to 16TB.
>
> Not that this answers your question, as the Linux kernel has supported
> 4kB sectors for years and AFAIK it does not need any special
> configuration options to do so...
>
> andrea

It's always a good idea to check alignment on the newer disks. Here's a 
doc [1]; but it's not always clear how to ensure proper alignment. 
Supposidly the newer tools do this automation, but it's not 100%; ymmv.


[1] 
https://www.ibm.com/developerworks/linux/library/l-linux-on-4kb-sector-disks/

Many disk are hybrids of the 512/4906 sector size.



hth,
James