On Mon, Jun 16, 2003 at 11:32:49AM +0200, Heinz J . Mauelshagen wrote: > On Sat, Jun 14, 2003 at 10:07:54PM +0200, Herbert Poetzl wrote: > > On Sat, Jun 14, 2003 at 02:45:11PM +0200, Svetoslav Slavtchev wrote: > > > Quoting Herbert Poetzl <herbert@13thfloor.at>: ... some highmem live-lock issue [removed] ... > > I posted my results a month ago, but I digged them > > out again, because together with your results, it > > sheds new light on that issue ... > > > > mine raw disc md(raid5) lvm on md > > ----------------------------------------------------- > > hdparm 14694.40 34129.92 18667.52 > > dd 1024k 14988.22 34732.56 18647.98 > > dd 32k 15516.06 33945.48 18862.67 > > > > yours raw disc md(raid5) lvm on md > > ----------------------------------------------------- > > hdparm 46151.68 60682.24 49459.20 > > > > in both cases the lvm lies about 3MB over the raw > > disc throughput, regardless of the md values ... > > The reason probably is LVMs read ahead. hmm, so it's a feature? seriously, what can be done about it? it surely doesn't hurt on a 50M per disk throughput system, but 34M/19M seems cruel, especially because I'm thinking of adding one or two more discs to the system, which probably leads to a 50M/19M situation with lvm? TIA, Herbert PS: why am I receiving your emails twice, with alternating From headers? I actually get them three times as I'm subscribed to the list too ;) Heinz.Mauelshagen@t-online.de (Heinz J . Mauelshagen) "Heinz J . Mauelshagen" <mauelshagen@sistina.com> (one list copy) _______________________________________________ linux-lvm mailing list linux-lvm@sistina.com http://lists.sistina.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
