No support for thin provisioning on top of RAID in a cluster
While RAID logical volumes and thinly provisioned logical volumes can be used in a cluster when activated exclusively, there is currently no support for thin provisioning on top of RAID in a cluster. This is the case even if the combination is activated exclusively. Currently this combination is only supported in LVM's single machine non-clustered mode. (BZ#1014758
Anaconda installation can fail when LVM or md device has metadata from a previous install
During Red Hat Enetrprise Linux 7 installation on a machine where a disk to be multipathed already starts with LVM or md metadata on it from a previous install, multipath will not get set up on the device, and LVM/md will get set up on one of the path devices while Anaconda is starting up. This can create problems with Anaconda, and cause the installation to fail. The workaround for this issue is to add
mpath.wwid=<WWID> to the kernel command line when booting up for the installation.
<WWID> is the wwid of the device that multipath should claim. This value is also the same as the
ID_SERIAL udev database value for scsi devices and
ID_UID for DASD devices. (BZ#1378714)