Linked by Adam S on Wed 15th Oct 2008 15:20 UTC
General Unix This article explores the virtualization features available to administrators across several UNIX hardware platforms. Discover what they have to offer and how their features compare to PowerVM.
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Article has incorrect information
by Arun on Wed 15th Oct 2008 15:53 UTC
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This article is riddled with fundamental inaccuracies. Most of this data has been available for over an year. Very poorly researched.

Introduced in 2007 on their SunFire line of servers, LDOMs enable customers to run multiple operating systems simultaneously. While LDOMs solved a huge deficiency in Sun's virtualization strategy, it has many inherent flaws:

Scalability -- Only eight CPUs and 64GB RAM on one machine

Sun just announced a 4 chip UltraSPARC T2+ system that has 32 cores and 512GB Memory. Each core runs 8 threads. A domain can be assigned to each of these. So a 4-way UltraSPARC T2+ system can have 256 Logical domains.

Sun also has T2+ chip based 2 way and have much larger memory configurations than 64GB.

Server-line -- Only low-end Sparc servers are supported

Low end and Midrange with the introduction of T5440.

No Dynamic allocation between partitions

CPUs can be dynamically added and removed ever since the first release.
"All CPUs exposed by the hypervisor are referred to as virtual CPUs. On
platforms supporting logical domains, such as a Sun Fire T1000 and T2000
system, each of the cores of the system has four executing threads, represented
as virtual CPUs by the hypervisor. Thus, an eight-core Sun Fire T2000 server
would have 32 virtual CPUs able to be partitioned between the various logical
domains on the system. With this release of Logical Domains 1.0 software, virtual
CPUs are able to be dynamically reconfigured; that is, removed or added to a
guest logical domain while the guest operating system is running, without
requiring a reboot. Note this requires a specific version of the Solaris Operating
System to be installed in the guest domain and might not work with other
operating environments.

You can have 32 domains on T1, 64 on T2, 128 and 256 on T2+ based systems depending on the configuration.

VIO servers. These are special partitions that allow you to service resources to VIO clients. The servers own the actual resources, which are network adapters or disk I/O. These partitions save money and provide flexibility by allowing partitions to shared I/O resources. Shared Ethernet and virtual SCSI are the solutions that allow for sharing network and disk I/O.

Sun's Logical Domains provides the exact same capabilities. Some how the author missed that while doing research as well.

What could have been a good comparison ends up being a typical IBM marketing FUD piece.

Edited 2008-10-15 16:02 UTC

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