[rhelv6-beta-list] Can RHEL6 installer align the disk partition with 4k-sector or raid stripe size?

[Justin Clift]

On 06/08/2010 09:37 AM, Nico Kadel-Garcia wrote:
<snip>
> This is thoughtful, but it's relevant only to physical media, not
> virtual images. Until virtualization "disks" are configurable as "4096
> byte block devices", the emulated disks have a behavioral issue that
> the guest OS's cannot see.

As a data point, one of the test setups we have here exports luns over 
the network with 4k sector sizes.  These are mounted on host servers, 
and assigned directly to guests for use as storage.

 From the guests' perspective these are physical disks with real 4k 
sector sizes.  If the guests utilities only support 512 byte sectors, 
then strange errors and bad things happen due to the mismatch. 
(incorrect usage of space, no ability to boot, etc).

Using (very recent) guests that support 4k sectors (through using recent 
grub and parted), and the guests install and operate fine.

On the plus side, using 4k sector sizes for guests over the network like 
this seems to have a very positive effect on the backend disk IO 
performance.

Regards and best wishes,

Justin Clift

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