You are right that devicemapper (basically lvm snapshots for storage, used as an alternative to aufs/btrfs on many distros including Red Hat) has been a source of headaches for us. It is relatively obscure (we knew we were in trouble when googling libdevmapper error messages returned our own source code as the first result) and frankly not pleasant to work with.
But, the good news is that we have made progress recently. In fact the 1.5 release includes several improvements to devicemapper. And as of last week, Red Hat has volunteered a dedicated engineer to escalate devicemapper problems. So, fingers crossed things will be even better in the next release :)
Another alternative is to switch storage drivers: aufs and btrfs are popular options.
But, the good news is that we have made progress recently. In fact the 1.5 release includes several improvements to devicemapper. And as of last week, Red Hat has volunteered a dedicated engineer to escalate devicemapper problems. So, fingers crossed things will be even better in the next release :)
Another alternative is to switch storage drivers: aufs and btrfs are popular options.