On Mon, Sep 09, 2002 at 12:04:11AM +0200, Luca Berra wrote: > On Sun, Sep 08, 2002 at 11:44:41PM +0200, Xavier Montagutelli wrote: > >On Sat, 7 Sep 2002, Chris Jantzen wrote: > > > >>VFS lock patch, yes, but my real question is: why is the raid5 buffer > >>cache constantly thrashing back and forth? I assume this has to do with > ... > >I have exactly the same symptoms with the same configuration (md + lvm + > >reiser) ; the raid5 cache size keeps changing when I start using > >snapshots. Does someone have some tips to avoid/explain this ? > > The r5 cache needs a fixed request size, Neil once explained me, but i > do not recall the exact details now, when the md layer receives a > request with different size, it has to be emptied and recreated with > the new size. > This is the meaning of the message, it is harmless, except for > performance, at the moment the best that can be done about it is > commenting out the message. Well, I know it's harmful and I know that's exactly why it happens. I want my performance though! :-) I was wondering if any of the deep LVM guru's could say whether SECTOR_SIZE could be safely bumped up. Thanks for the input and I think I'll wait a few more days before making a hard decision. -- chris jantzen kb7rnl =-> __O Insert witty comment here. _`\<,_ http://www.maybe.net/ (*)/ (*) _______________________________________________ linux-lvm mailing list linux-lvm@sistina.com http://lists.sistina.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html
