Re: Severe slowdown with LVM on RAID, alignment problem?

On Fri, 29 Feb 2008 00:53:06 -0700, Maurice Hilarius [off-list ref]
wrote:

Michael Guntsche wrote:

quoted

..
While the result for XFS is different, reading is actually faster, the
differnece between xfs and xfs on lvm is still there.

Great. At least now the figures are more realistic.

quoted

pvcreate was called so that the first PE starts exactly at 256K, no

sunits

quoted

where used with mkfs.xfs for the lvm case.

I still do not understand the read output at all.

That is certainly a puzzle.

Is it possible that my computer is just too slow to get good read results?
I wonder since writing seems to be nearly similar.
I just tried with an ext3 FS.

Version 1.03c       ------Sequential Output------ --Sequential Input-
--Random-
                    -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec
%CP
lvm-al8g-ext3    8G           45029  27 22436  29           55034  45 192.0
 3

While reading is a little bit faster it's nowhere near the speed I get on
md0 itself.

Kind regards,
Michael