Oracle serves up SPARC 'live migration'

No downtime for migration and maintenance.

Organisations running workloads on Sun SPARC T-Series servers can now execute live migrations, folowing the release of Oracle’s latest VM hypervisor.

The newly announced Oracle VM Server for SPARC 2.1 will allow up to 128 virtual machines on a single system.

The VM server will also offer SPARC users live migration out of the box, which “enables users to migrate an active domain to another host machine while maintaining application services to users,” according to Oracle.

Oracle promised its version would eliminate application outages and server downtime during maintenance. 

Rivals such as VMWare offer live migration of virtual machines on x86 servers (dubbed vMotion), which comes bundled with vSphere 4.1 released last year.

Oracle's alternative is based on a redesigned, Sun-inherited technology, previously known as “LDoms” or Solaris Logical Domains for its VM for SPARC systems.

Oracle took a different tack to how LDoms implement virtual machines by offering each instance a dedicated CPU, according to Jeff Savit, a principal sales consultant at Oracle, formerly Sun’s principal field technologist for areas related to Solaris, Linux and virtualisation.  

Prior versions offered "warm migration", which staggered the migration process by suspending a guest operation while its memory contents and state were transferred from the source host to the target, and then resumed, said Savit.

The older process relied on a set of CPUs available to Oracle’s T-Series SPARC chip multithreading servers, while Oracle VM Server for SPARC gives each “domain” or virtual machine its own CPUs, thus lowering overheads and liberating a VM from running in a lower privilege mode. 

“No time-slicing is needed, and guest operating systems can execute instructions that change machine state (eg: memory mapping or interrupt masks) run safely (in the virtual machine only) and without penalty. An elegant solution to a 40-year old problem,” Savit noted.

One Oracle customer believed that the design of Oracle’s VM feature, in which the hypervisor is visible to the kernel, should put it ahead of rival technologies by VMware and Microsoft, according to a report in Search Data Centre.

But upgrading the operating system to use the VM migration tool would prove a "nightmare", according to the report, which also pointed out that many SPARC-based workloads would be considered too mission critical to risk migrations.