Correct - for Windows Server 2008 and 2008 R2, you need a few things to start:
- You need two machines running Windows Server 2008 or two machines running Windows Server 2008 R2 Enterprise or Datacenter (you cannot use 2008 or 2008 R2 standard for a failover cluster) - these should be identical, but it's not entirely necessary. It does make things *much* easier to set up and troubleshoot though, so it is strongly recommended these be identical.
- You need an external disk array available via iSCSI or fiber channel - you can no longer use regular SCSI to connect to an external array as you could with Windows Server 2003 or Windows 2000 Server. Note that if you use iSCSI, the external device *must* support SCSI-3 persistent reservations (SCSI-3 PR). Storage server devices running Windows Server 2008 Storage Server and Windows Server 2008 R2 Storage Server products can do this, products running the latest versions of FreeNAS can do this, and most reputable OEM hardware SAN (not NAS, but SAN) solutions can do this as well, but you should always ask first. Some NAS devices can do this, but most cannot, so you need to make sure any external iSCSI device can support SCSI-3 PR. If you use fiber channel SAN or NAS devices and host-based adapters (HBAs), this is not an issue.
- You should have at least two network cards in each machine - one card connected to the other server via a crossover cable or a private switch that acts as the "heartbeat" network, and one card connected to your public network for users to use to access the cluster. This is not 100% necessary (you can put heartbeat and public networks on the same network card), but it can cause issues with heartbeat if the cluster's network card is otherwise busy, and as such this should be avoided at all cost. Most servers nowadays ship with at least two network interfaces, so use them
.
That's really about it - once you've configured the network cards and attached the SAN or NAS via fiber or a SCSI-3 PR-compliant iSCSI network (and used the iSCSI initiator in Windows to connect to that iSCSI device on each server), you can run the cluster wizard on each node to create the cluster and join the first node, and then on the second server to join it to the newly-created cluster.
Technet has a good document on 2008 R2 clusters
here on setting up a generic cluster, guides for SQL clustering
here and
here, and there's a good step-by-step guide with pictures
here from a non-Microsoft source. My recommendation is to download evaluation versions of
Windows Server 2008 R2 and
SQL 2008 R2, install
Hyper-V or
VMWare, and use that to test and break/play with iSCSI clustering until you figure it out (both guides are for 2008, but translate to 2008 R2 without really any changes).
