Mike Snitzer b123a82d73 Change default alignment of pe_start to 1MB. ... The new standard in the storage industry is to default alignment of data areas to 1MB. fdisk, parted, and mdadm have all been updated to this default. Update LVM to align the PV's data area start (pe_start) to 1MB. This provides a more useful default than the previous default of 64K (which generally ended up being a 192K pe_start once the first metadata area was created). Before this patch: # pvs -o name,vg_mda_size,pe_start PV VMdaSize 1st PE /dev/sdd 188.00k 192.00k After this patch: # pvs -o name,vg_mda_size,pe_start PV VMdaSize 1st PE /dev/sdd 1020.00k 1.00m The heuristic for setting the default alignment for LVM data areas is: - If the default value (1MB) is a multiple of the detected alignment then just use the default. - Otherwise, use the detected value. In practice this means we'll almost always use 1MB -- that is unless: - the alignment was explicitly specified with --dataalignment - or MD's full stripe width, or the {minimum,optimal}_io_size exceeds 1MB - or the specified/detected value is not a power-of-2		2010-08-12 04:11:48 +00:00
..
config.c	Use __attribute__ consistently throughout.	2010-07-09 15:34:40 +00:00
config.h	Fix the "const discarded" warnings introduced in the unknown segment patch.	2009-10-22 10:38:07 +00:00
defaults.h	Change default alignment of pe_start to 1MB.	2010-08-12 04:11:48 +00:00