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

[caiqian at redhat.com]

> I assume that the original poster mant "4k block size". 4k
> sectors.... doesn't make much sense.
> 
> So far as I can tell, this only works with hard drives which are
> detected as 4K block size. According to my preliminary tests, it does
> *NOT* work with VMware, Xen, or KVM disk images. This is an important
> feature for certain attached storage devices, such as NetApps, which
> behave very badly if the partitions of virtual disk images are not 4K
> aligned. It should, ideally, be a simple setting for disk
> configuration in Anaconda and especially in a virtual machine setup
> tool, but even fdisk mishandles this: at least up through RHEL 5.
> 
> You see, you can set the block size with fdisk inside a '%pre'
> statement. But if you don't have a partition set, fdisk automagically
> reverts the block size to 512 for you. This means that in order to
> preserve the block size information for Anaconda's disk configuration
> tools, which have *no* options to select specific sectors to start or
> end partitions, or to do this 4K block size, you have to set aside a
> partition that anaconda will not touch and that will preserve the4096
> block size setting. That's.... fairly awkward to allocate and recover
> later.
> 
> I've also found no way to tell Anaconda "I've built the partitions for
> you in %pre: use *THESE* partitions for *THOSE* mount points, and
> don't try to repartiton them." If someone knows a way, I'd love to
> hear it.

Have you seen this in the RHEL6 Beta manual?
http://www.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6-Beta/html/Storage_Administration_Guide/newstorage-iolimits.html#iolimits

"As of this release, boot support for 4K sector devices is planned, but not yet supported."

C.