On 10/6/2010 1:40 PM, Petr Rockai wrote: > Yes, (write) performance is a concern. Otherwise, what you describe is > perfectly valid and achievable with LVM. It is? What happens when the log device fails? >> I don't know how LVM handles issues of PVs that are not permanently dead >> and come back on line again later. The md driver uses a generation count in >> the super block to determine which is newer. (How is that updated without loss >> of efficiency?) > > LVM has a generation counter as well. It's only updated on metadata > writes though, so it doesn't cost anything. (Log is not part of metadata > in this sense.) When you lose a leg (and use dmeventd), the metadata on > the remaining PVs is updated to say that. The leg is also yanked from > the mirror. You can add it as a fresh image (with full resync) if it > ever comes back. Why a full resync? With mdadm, it just keeps flagging the dirty chunks so it only has to copy those when the other disk returns. _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
