Anaconda/installer aligning partitions during install and SAN performance

[Pasi Kärkkäinen]

Hi!

When anaconda initializes a disk and creates a new partition (the default partition layout),
the first partition is set to start from the sector 63. 

In normal cases and with normal harddisks this is fine. 

But if your disk is a SAN LUN (iSCSI, FC), this could cause all the IO to be
"misaligned", causing a performance drop. Many SAN arrays want the partitions
to be aligned on a 8 kB boundary, or some even on 64 kB boundary. 

Would it cause problems if anaconda automatically aligns partitions to start 
from a sector that is a multiple of 8 (or even 64 kB) ? Or maybe add an option 
to specify how to align the partitions? 

VMware document about aligning partitions for ESX/VMFS for optimal
performance: 

http://www.vmware.com/pdf/esx3_partition_align.pdf

Comments welcome!

-- Pasi