VM functions that Linux^™ can exploit

Performance

• VM provides multi-image support and can run hundreds of Linux guests simultaneously.
• Using IUCV or virtual CTCA devices, VM supports very high-performance networking among Linux guests.
• These same facilities can be used to establish high-speed connections to VM's TCP/IP stack.
• VM exploits large N-way processor architectures that Linux cannot yet use effectively. Coupled with VM's ability to run multiple Linux guests, this allows more resources to be devoted to Linux-based applications on a single system.
• Data-in-memory support, provided by VM Virtual Disks in Storage and Minidisk caching, provides transparent, high-speed data access for Linux guests.
• VM exploits expanded storage on behalf of Linux guests automatically and transparently.

• Minidisk I/O and processor error recovery are built in to VM and provided automatically, relieving the Linux guest of this responsibility.
• Dynamic I/O reconfiguration support in VM allows real devices to be added to or removed from the configuration without disturbing Linux guests.
• Support for CP sparing in VM allows additional processor capacity to be brought online as needed.
• VM simplifies the ability to provide standby systems for immediate backup of failing applications.

• VM tracing, diagnostic, and debugging facilities are extensive, simplifying making kernel and device driver development, as well as supporting problem data capture and analysis for production systems.
• Extensive performance measurement, reporting, and control facilities in VM can be used to manage Linux guests.
• Facilities for virtual machine scheduling and automation can be extended to perform these functions for Linux guests.
• Because no real resources need to be dedicated to a Linux virtual machine, creating and deleting them is quick and easy.

• The Linux minidisk driver uses VM facilities to access DASD and thus supports all devices that z/VM and VM/ESA support in a device-independent manner and with complete error recovery.
• Temporary disks can be used to meet interim needs for additional Linux DASD space.
• VM simulates and virtualizes a variety of devices that Linux can exploit, including Channel-to-Channel Adapter (CTCA) and 3215 console devices.
• VM can be used to create a complex environment for test purposes without requiring real hardware duplication.
• A Linux virtual machine may define and use up to 64 virtual processors, regardless of the number of real processors in the hardware configuration.
• VM facilitates resource sharing - of CPUs, Memory, DASD, and network - that can maximize resource utilization while minimizing expense.
• As need arises, additional Linux guests can be created quickly and easily to ensure that user productivity is not constrained.
• The Linux kernel can be saved as an IPLable named system to simplify the boot process and ensure that one or more standard kernel configurations are available to all Linux guests.