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Oracle VM Server for SPARC

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Logical Domains
Company typeTechnology / Software solution
IndustryVirtualization software
FoundedApril 2007
FounderSun Microsystems
FateRenamed Oracle VM Server for SPARC in 2010
ProductsLogical Domains virtualization technology
ParentOracle Corporation (after 2010)

Logical Domains (also known as LDoms or LDOM) represent the virtualization and partitioning solution designed for SPARC V9 processors, initially introduced by Sun Microsystems in April 2007. After the Oracle acquisition of Sun in 2010, the technology was renamed Oracle VM Server for SPARC beginning with release 2.0.

Each domain functions as an independent virtual machine with configurable hardware allocations. Domains can be securely migrated live between physical hosts while operational. Within Logical Domains, operating systems can be independently launched, halted, or rebooted. The platform supports dynamic reconfiguration, enabling CPUs, memory, or I/O devices to be added or removed without requiring a restart. Additionally, Dynamic Resource Management facilitates automatic adjustment of CPU allocation based on workload demands.

Supported hardware

The SPARC hypervisor operates in a hyperprivileged mode introduced with the sun4v architecture. As of October 2015, supported processors include UltraSPARC T1, T2, T2+, SPARC T3, T4, T5, and M5, M6, M10, and M7 families. UltraSPARC T1 is compatible only with Logical Domains versions 1.0 through 1.2; subsequent T-series models support version 2.0 and beyond.

Major supported platforms comprise:

UltraSPARC T1-based:

  • Sun/Fujitsu SPARC Enterprise T1000/T2000
  • Sun Fire T1000/T2000
  • Netra T2000/CP3060 Blade
  • Sun Blade T6300

UltraSPARC T2-based:

  • SPARC Enterprise T5120/T5220
  • Sun Blade T6320
  • Netra CP3260/T5220

UltraSPARC T2 Plus:

  • SPARC Enterprise T5140/T5240 (dual sockets)
  • SPARC Enterprise T5440 (quad sockets)
  • Sun Blade T6340 (dual sockets)

SPARC T3:

  • SPARC T3-1/1B (single socket)
  • SPARC T3-2 (dual sockets)
  • SPARC T3-4 (quad sockets)

SPARC T4:

  • SPARC T4-1/1B (blade server)
  • SPARC T4-2 (dual sockets)
  • SPARC T4-4 (quad sockets)

SPARC T5:

  • SPARC T5-1B (blade)
  • SPARC T5-2/4/8 (ranging from two to eight sockets)

SPARC T7:

  • SPARC T7-1/2/4 (one to four sockets)

M-Series:

  • Oracle SPARC M5-32/M6-32 (32 sockets)
  • Fujitsu M10-1/4/4S (up to 64 sockets)
  • Oracle SPARC M7-8/16 (eight to sixteen sockets)

The solution consists of a hypervisor embedded within the server firmware alongside the Logical Domains Manager software that runs on Solaris within the control domain. Each version of Logical Domains mandates a minimum hypervisor firmware level.

Logical Domains take advantage of the chip multithreading (CMT) design found in "CoolThreads" processors—offering up to 32 cores per chip with four to eight hardware threads each—allowing for near-native performance without the usual virtualization penalties.

A single server can host one domain per hardware thread, supporting up to 128 domains on single-socket systems such as the UltraSPARC T3. Servers equipped with multiple CPUs scale their domain counts accordingly; M-series servers can be partitioned into physical domains capable of hosting as many as 128 logical domains each. Administrators have the flexibility to modify CPU threads, memory capacity, and virtual I/O devices assigned to each domain dynamically without necessitating a reboot.

Starting with Oracle VM Server for SPARC version 2.1, guest domains connected to shared SAN or NAS storage can be live migrated securely across servers without interruption. During this migration process, memory contents are encrypted utilizing processor-based cryptographic accelerators to ensure data security.

Logical Domain Roles

Logical domains are primarily distinguished by their designated roles, which encompass:

  • Control domain
  • Service domain
  • I/O domain
  • Root domain
  • Guest domain

The control domain oversees the logical domain infrastructure, handling the allocation of system resources and the setup of guest domains. It also delivers critical services such as virtual console access and frequently serves as a service domain.

Service domains provide virtualized resources like virtual disks and network switches to other domains. Typically, guest domains conduct their I/O operations via service domains, which often operate as I/O domains with direct physical device connections. These domains facilitate virtual LANs, SANs, and bridging to hardware devices. Disk images may reside on local storage, SAN arrays, UFS/ZFS file systems, NFS shares, or iSCSI targets.

Although control and service roles can be merged within a single domain, it is advisable to run user applications outside these domains to ensure optimal system stability and performance.

I/O domains possess direct control over PCI buses, cards, or SR-IOV functions, allowing either native I/O throughput or device sharing as virtual resources to other logical domains.

Root domains manage the PCIe "root complex" along with its connected slots, providing access to physical I/O hardware. These root domains represent a specialized category of I/O domains. UltraSPARC T1 servers support up to two root domains (with one being the control domain), while UltraSPARC T2 Plus, SPARC T3, and SPARC T4 systems can accommodate up to four root domains depending on the number of PCIe root complexes installed. SPARC T5 servers allow for as many as sixteen root domains. Deploying multiple I/O domains enhances fault tolerance.

Guest domains operate independent operating system instances without directly managing hardware or service functions; instead, they depend on other domains for these capabilities.

Supported Guest Operating Systems

Official support is provided for running Solaris 10 11/06 and subsequent updates, as well as all versions of Solaris 11 within logical domains.

Additional operating systems that can function within logical domains but lack official support include:

See also

External links

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