Sun Microsystems White Paper Sample

LDoms allows server resources to be partitioned and allocated to virtual machines. Resources that can be partitioned include individual CPU threads (virtual CPUs), the processor’s cryptographic acceleration modular arithmetic units (MAUs), memory, PCI root nexus nodes (or “PCI buses”), and network interface units (NIUs). Architecturally, LDoms is a Type 1 hypervisor because the technology runs on a bare machine and provides each domain with the illusion that it is running on its own dedicated hardware — in this case hardware having the SPARC sun4v architecture. With LDoms, the control domain manages the hypervisor. I/O is performed through virtual devices to one or more I/O domains that actually perform physical I/O on behalf of a domain (these are sometimes referred to as service domains). Figure 1 illustrates a server with a control domain that manages the hypervisor, two I/O domains that perform physical I/O, and three guest domains. In a typical installation, a combined control and I/O domain performs both functions.