Today in a working meeting, which was being discussed the possibility of expanding the current capacity of a RAC (this system has two nodes) it was evaluating the possibility of increasing the number of CPUs and system memory. Someone has said that as the machines were very old we could buy a new machine and include it in the cluster. The issue is that current machines are so old that they are no longer sold, so you would have to buy a different machine. Is this possible?, Oracle supported it technically, is like having two types of cabin storage. Keep in mind some of the following limitations (there are more but you should refer to the vendor documentation).
- All the nodes to run the same Operating System binary, all Windows 2008 or all nodes RedHAT 7 or all nodes Solaris 11…
- All nodes must be the same architecture (32 or 64 Bit).
- Nodes that have different hardware configurations (I.E. number of CPUs) are supported.
However, from the standpoint of experience and daily work, this can be a problem if the application does not support balance load or is not designed for it. Apart cluster is unbalanced, of course, there any 100% balanced cluster (nodes may have other applications or databases) and this involves more manual labor by someone (an operator, DBA, …).
HTH – Antonio NAVARRO