ELRepo repository and DRBD availability
ELRepo is a community repository for Linux distributions that are compatible with Red Hat Enterprise Linux, which CentOS and Scientific Linux are derivatives of. ELRepo has hardware-related packages (especially drivers) as the primary focus in order to enhance or provide functionality that is not present in the current kernel. Thus, by installing the corresponding package, you save yourself from the pain of having to recompile the kernel only to add a certain feature, or having to wait for it to be supported by upstream repositories, or for the feature to be included in a later kernel release. The ELRepo repository is maintained by active members of the related distributions (RHEL, CentOS, and Scientific Linux).
DBRD, as made available by ELRepo, is intended primarily to evaluate and get experience with DRBD on RHEL-based platforms, but is not officially supported by Red Hat and LINBIT, the creators of DRBD. However, following the procedures outlined...