On Tue, Feb 15, 2011 at 04:13:15PM -0600, Jonathan Brassow <jbrassow@xxxxxxxxxx> wrote: > > Oh, do I read the code correctly that rhel6/upstream always reads from > > the first mirror and switches only in case there is a read failure? > > yes Hm, was the was reason for dropping the round robin feature? I thought that round robin causes better performance, given that IO reads are done in an async way. Did I miss something or just nobody ported the patch to RHEL6/upstream? > Perhaps, but if you don't encode this in the LVM metadata, you will > have to perform the action every time you reboot. Instead, you could > reorder the devices in userspace and reload the table. I was not aware such a reorder is possible. That patch then does not make too much sense, agreed. ;) (Do you have a pointer to some documentation on how that reorder can be done? I can't find anything about reorder in the lvconvert/dmsetup manpage. > The basic component that covers RAID456 is available upstream, as you > saw. I have an additional set of ~12 (reasonably small) patches that > add RAID1 and superblock/bitmap support. These patches are not yet > upstream nor are they in any RHEL product. Then what is the recommended platform to hack dm-raid? I have RHEL6 at the moment. Is it OK to try to cherry-pick the single commit from upstream + apply your patches or is it better to install rawhide where the kernel is already 2.6.38rc5 (as far as I see) and only apply your patches there? > Yes, I have a script called 'gime_raid.pl' that creates the device- > mapper tables for dm-raid. Eventually, this will be pushed into LVM, > but it was much easier (for testing purposes) to start with a perl > script. Sure. :) > For convenience, I've attached the patches I'm working on (quilt > directory) and the latest gime_raid.pl script. Thanks! -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
