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Sun Microsystems has updated the Logical Domain (LDom) server
virtualization hypervisor for its Niagara family of servers, and used
the occasion to brag about some benchmark results it has posted on a
popular Java application test.
The LDom hypervisor is only available for Sun and Fujitsu servers
based on Sun's Sparc T1, T2, and T2+ servers, which pack multiple Sparc
cores with from four to eight threads each, into a single chip package.
These Sparc T series chips are available in single-socket and
two-socket configurations that span a performance range that is roughly
equivalent to entry and midrange x64 and RISC/Unix boxes.
The LDom hypervisor allows each thread on a Sparc T machine to be
configured as a virtual machine, capable of running a complete instance
of the Solaris 10 operating system, including its own Solaris kernel
and file system.
The LDoms can also span multiple threads if customers want to
dedicate more compute power to a partition. LDoms are distinct from
Solaris containers, which offer a different kind of virtualization
commonly called a virtual private server and that creates what looks
like separate Solaris instances on a machine, but these instances run
off a shared kernel and file system. This VPS approach makes patching
and updating easier, but it does mean that all of the container eggs
are in the same kernel/file system basket and are not fully isolated
instances like LDoms allow.
The LDom software is available for free as a download through Sun's CoolThreads tool site,
and the company is obviously pitching its software and its freeness
against the various hypervisors available for x64 and other RISC/Unix
platforms.
The company stretches the truth quite a lot, though, when claiming
LDoms can save IT shops up to $10,000, considering that XenServer
Enterprise is now free, VMware ESXi is free with $450 a year in support costs, and IBM has offered a base PowerVM license at $40 per processor core on its Power6 machines since early last year.
That said, LDoms appears to be a good technology, and it is exactly
the kind of virtualization that Sun and Fujitsu need for their entire
Sparc-based systems. It would be incredibly stupid if LDoms are not
part of the future Rock UltraSparc-RK processors, expected in Supernova servers in the second half of this year.
With the LDom 1.1 hypervisor update, Sun has added "significant" but
unquantified performance enhancements, and - more importantly for many
Sparc shops - has a live migration feature called domain mobility.
This will allow the dynamic migration of domains within a machine
and across a network of machines, to improve resiliency and for
managing energy consumption on a group of servers. It does this by
consolidating running LDoms onto the smallest number of physical
machines and shutting down boxes that are not needed.
The LDom 1.1 update also includes virtual I/O dynamic
reconfiguration, allowing virtual networks and storage to be added to a
domain on the fly, without requiring a reboot of the LDom. The update
also includes a feature called hybrid I/O for network interfaces, which
lets a virtual network interface in a guest domain supporting Solaris
to directly access a physical network interface in an LDom that has
been set up to be a dedicated I/O domain. The updated hypervisor also
includes support for VLANs adhering to the 802.1Q standard, and virtual
disk failover.
As part of the LDom 1.1 announcement, Sun took a swipe at IBM's
Power 570 AIX boxes based on their respective test results on the
SPECjAppServer2004 benchmark. This test, created by the Standard
Performance Evaluation Corporation, is meant to measure the performance
of a system - or collection of machines - as Java application server.
Sun touted the 6,335 operations per second (OPS) performance it was able to get on a quad-socket T5440 server
using 1.4GHz Victoria Falls Sparc T2+ chips and 128GB of main memory, a
test it ran last October atop Oracle's WebLogic SE 10.3 application
server and Solaris 10.
However, last month Sun ran the same SPEC test on four two-socket
T5140 servers, each with 1.2GHz Sparc T2+ processors and with 32GB of
memory, that was able to support 9,501 OPS on the SPECjAppServer2004
benchmark.
For fun, Sun picked on IBM's Power 570 server equipped with four
4.7GHz cores and running AIX and IBM's own WebSphere V6.1 app server,
which delivered a mere 1,198 OPS on the same test.
Sun claimed it can consolidate up to four racks of IBM's Power 570
machines onto two T5440 servers at about one-fifth the hardware cost.
It would take a long time to peel that claim apart, but suffice it to
say Sun seems to be ignoring that IBM can now cram up to 32 cores in a
single system image with the Power 570. It has been able to do this
since last fall but could not do when it ran this SPECjAppServer2004
test back in August 2007 as its first Power6 machines launched.
I think it is time to look at some SPEC, TPC-C, SAP, and other tests
and do a little more detailed analysis based on cost and form factor.
Vendors game this stuff way too much. If none of you want to do it, I
will.
Read the original article: http://www.theregister.co.uk/2009/02/27/sun_ldom_update/
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