BackgroundWith the initial release of Windows® Compute Cluster Server 2003 (WCCS), Microsoft brought the power of high performance computing (HPC) to the commercial mainstream. Windows Compute Cluster Server was built to shorten user time-to-insight for HPC workloads through easier deployment and management. WCCS provided a complete and integrated cluster environment, including the operating system, Job Scheduler, Message Passing Interface v2 (MPI2) support, and cluster management and monitoring components.

The release of Windows® HPC Server 2008 builds on the strengths and ecosystem of WCCS to allow Windows-based HPC to scale to support even larger deployments, while advanc-ing every facet of your HPC cluster with a new scheduler, better provisioning based on the Windows Server® 2008 Windows Deployment Services technology, a faster Microsoft Message Passing Interface (MS-MPI) that includes new NetworkDirect support, and a new management interface.

Enterprises that have invested in WCCS clusters have already experienced accelerated time-to-insight through a powerful compute cluster. With the availability of Windows HPC Server 2008 (HPCS), some will opt to migrate or convert existing clusters to HPCS, but many others will expand new clusters, allowing their users to solve new problems and to take advantage of the improvements and new features in HPCS. In this paper, we highlight the requirements for having both WCCS and HPCS clusters on the same network , while providing a comparison of features and capabilities.

Version ComparisonThe minimum hardware requirements for HPCS clusters are essentially similar to WCCS clusters. Both require either AMD64 or Intel EM64T processors with a minimum of 512 MB of RAM. HPCS, however, supports up to 128 GB of RAM per node. The hard disk require-ments for HPCS are significantly greater because of the change in the underlying base operating system—50 GB compared to 4 GB for WCCS. Both support the same network configurations, using from one to three network cards per node.

The underlying operating system for WCCS was Windows Server 2003, Service Pack 1 (SP1). For HPCS, the underlying operating system is Windows Server 2008. Individual compute nodes can use any x64 version of the base operating system except the Web Edition. HPCS uses Windows Deployment Services for deploying compute nodes, compared to Remote Installation Service (RIS) for WCCS.

A comparison of features is shown in Table 1.

Node Compatibility

Head nodes using WCCS can control compute nodes only in WCCS clusters, • and head nodes using HPCS can control compute nodes only in HPCS clusters. Compute nodes in each cluster must be of the same base operating system as the head node—there is no support for mixed WCCS/HPCS clusters.

Head nodes of HPCS clusters can be redundant, using Windows Server 2008 • Failover Clustering. There is no redundancy support for WCCS head nodes.

Individual nodes of a compute cluster can belong to only one cluster—either • WCCS or HPCS, but not both.

Windows HPC Server 2008V1 and V2 Compatibility

OverviewWith the release of Windows® HPC Server 2008, existing Windows® Compute Cluster Server 2003 customers can choose to add new clusters side-by-side with their existing clusters. This datasheet covers the basic requirements for coexistence.

Feature Windows Compute Cluster Server 2003

Windows HPC Server 2008

Operating System Support Windows Server 2003 SP1 Windows Server 2008 HPC Edition, Standard (64-bit), Enterprise (64-bit), DataCenter

Processor Type Support X64 (AMD64 or Intel EM64T) X64 (AMD64 or Intel EM64T)

Maximum number of sockets 4 CPUs 4 CPUs (HPC Edition)

Maximum amount of memory 32 GB of RAM 128 GB of RAM (HPC Edition)

Systems Administration User friendly interface of Administra-tor’s console enabled simpler comple-tion of essential tasks such as config-uring cluster networking topology, setting user permissions, and monitor-ing jobs.

New Administrator console user interface based on System Center. The new Administra-tor console integrates all aspects of cluster management and simplifies completion of essential tasks such as configuring cluster net-working topology, setting user permissions, and monitoring jobs and the operational health of the cluster.

Clusrun allows cluster administrators to submit a single-task job which by-passes the job queue and is immedi-ately executed on a specified set of compute nodes.

Clusrun UI was improved and now allows administrator to run scripts in parallel across the cluster.

Cluscfg configuration commands New features such as Node Templates lever-age Windows Deployment Services to signifi-cantly improve compute node deployment. Windows Deployment Services replaces the existing RIS technology for node provisioning.

Remote Installation Services used when deploying nodes with the auto-matic method.

Cluster administrators can create Node Groups to view and manage collections of nodes.

Integrated heat map provides an at-a-glance view of cluster-wide or node group status, performance, and utilization.

New cluster and node diagnostic testing allow a systems administrator to store, filter, and view test results and history.

Reporting is integrated into the management console.

Full support for all admin tasks using Power-Shell.

Head Node high availability support through Windows Cluster Services.

End User Tools Command-line interface PowerShell commands for scheduling and managing jobs. HPCS has full compatibility with existing CCS 2003 commands and also offers full support of PowerShell. More than 130 command-line tools enable automation of system administration tasks.

User console made submission and tracking of user jobs simple.

New Job Manager interface with improved support for parametric commands.

Custom job view filtering.

Feature Windows Compute Cluster Server 2003

Windows HPC Server 2008

Networking Wizard-driven configuration of net-work services such as DHCP, ICS, RIS, and the firewall.

Wizard-driven configuration of network serv-ices such as DHCP, RRAS, DNS, and Firewall.

Support for NetworkDirect, a new RDMA net-working interface built for speed and stability when using high speed interconnects.

MPI Security enabled Windows program-ming interface for MPICH-2 integrated with Windows Active Directory

Security enabled Windows programming in-terface for MPICH-2 integrated with Windows Active Directory

Integrated with new RDMA networking inter-face NetworkDirect.

MS-MPI events are integrated with Event Tracing for Windows

New shared memory communication imple-mentation.

Job Scheduling and Job Policies Support for Batch or MPI-based Jobs Job Templates for setting constraints/require-ments on jobs, including the ability to route jobs to specific sets of resources. Job Tem-plates also simplify end user job submission by enabling cluster administrators to specify default job term values.

Job Policies:• “First-come, first-served” scheduling• Backfilling of jobs• Exclusive scheduling• License scheduling

New Job Policies:• Resource Matching• Multilevel resource allocation. Resources include nodes, processors, and sockets.

• Adaptive allocation allows the growing and shrinking of of running jobs• Pre-emption of running jobs

New compute nodes designated as WCF Bro-kers allow interactive jobs to occur between clients and compute nodes. WCF Brokers can be added to support increased job capacity for SOA jobs.

Support for the Open Grid Forum HPC Profile for Job scheduler interoperability

Developer Tools C# and COM API for the CCS 2003 Job Scheduler

Support for interactive Service Oriented Ap-plications (SOA) using the Windows Commu-nication Foundation (WCF)

MS-MPI Scalable Microsoft HPC Pack 2008 API for job scheduling integration

Ability to export ETW tracing into jumpshot format for third party HPC tools support

Supports for all CCS 2003 COM APIs

Table 1. Feature Comparison

ManagementThe Microsoft® HPC Pack 2008 includes a new Administration Console for HPCS that is based on the Microsoft System Center interface, as well as a new scheduler interface, the HPC Job Manager. HPC Pack 2008 can be installed on business-class versions of Windows XP and Windows Vista®, as well as on Windows Server 2008. The management interface for WCCS is the Compute Cluster Administrator, which is part of the Microsoft® Compute Cluster Pack. The scheduler application is the Compute Clus-ter Job Manager. The Compute Cluster Pack can be installed on Windows XP Professional SP2 or later (including x64 Edition), business-class versions of Windows Vista, and Windows Server 2003 SP1 or later.

Side-by-Side InstallationAlthough both management interfaces can be installed on the same workstation, allowing side-by-side use, care needs to be taken to ensure that the appropriate job manager and administration interface is used to manage and submit jobs against the intended cluster, as you can see from the Compatibility Matrix for HPC clusters shown in Table 2.

NoteWhen installing the WCCS and HPCS client tools on the same workstation, users should be care-ful to ensure that the PATH and CCP_* environment variables are correctly set to make use of the ex-pected tools. For example, if PATH contains “C:\Program Files\Mi-crosoft HCP Pack\bin” before “C:\Program Files\Microsoft Compute Cluster Pack” then Command Line Interface (CLI) commands run on the system will use the HPCS CLI by default.

NoteThe CCPAPI.dll that provides API support for WCCS applications is installed as part of HPCS, allowing applications written against it to work without recoding or recom-piling.

WCCS Head Node HPCS Head Node

WCCS Client

CCPAPI.DLL Native WCCS Support Fully Supported

Compute Cluster Job Manager Native WCCS Support Fully Supported

v1 CLI Native WCCS Support Fully Supported

Compute Cluster Administrator Native WCCS Support Not Supported

HPCS Client

Microsoft.Hpc.Scheduler.DLL Not Supported Native HPCS Support

HPC Job Manager Not Supported Native HPCS Support

v2 CLI Not Supported Native HPCS Support

HPC Administration Console Not Supported Native HPCS Support

Table 2. Compatibility Matrix

API CompatibilityHPCS clusters are fully backward compatible with the WCCS API, allowing applications to smoothly move from a WCCS cluster to an HCPS cluster. However, applications will not be able to take advantage of new features in HPCS without breaking backwards compat-ibility with WCCS clusters because the API calls that support those new features are not backwards compatible with WCCS clusters. Independent Software Vendors (ISVs) who have applications that support WCCS can run those applications on both WCCS and HPCS, ensuring a smooth transition to HPCS for users and developers.

Command Line InterfaceThe Command Line Interface (CLI) for WCCS is also supported on HPCS, providing full backward compatibility of existing scripts. When running the CLI in a cluster environment that has both WCCS and HPCS, use the same WCCS syntax for any batch script that will be used on both types of HPC cluster to ensure that compatibility is maintained. HPCS includes the new Windows programming language, Windows PowerShell™. PowerShell is both a scripting language and an interactive shell that provides advanced capabilities for scripting and command-line use. PowerShell is not supported, however, for WCCS clusters.

Script MigrationExisting scripts written in any of the languages that were supported in WCCS will continue to work in HPCS, which maintains the same set of supported languages, plus the addition of Windows PowerShell. Scripts can be run on both WCCS and HPCS clusters as long as care is taken to not use features that are available only in HPCS.

MS-MPIMPI-based applications written for WCCS are compatible with HPCS and vice versa. The new, efficiency-boosting MS-MPI fea-tures in HPCS, such as NetworkDirect RDMA networking and re-designed shared memory communications, are intended to be transparent to MPI applications. WCCS-style submissions of all job types (including MPI jobs) are supported in HPCS. Windows HPC Server 2008 includes new job submission features which are integrated with MS-MPI, such as the ability to specify a number of nodes where a single MPI process will be started.

SummaryFor the benefit of customers who choose to add Windows HPC Server 2008–based clusters to existing Windows Compute Cluster Server 2003 environments, Microsoft has worked to ensure that HPCS maintains backward compatibility with existing WCCS clusters. If it worked in WCCS, it should work in HPCS! Windows HPC users can continue to use familiar applications and scripts on both versions of HPC clusters. Management and scheduler applications and tools from both WCCS and HPCS can be installed side-by-side on the same client workstation, helping to ensure full interaction with both clusters from a single user workstation. Where the same set of scripts and applications will be expected to work on both types of clusters, care should be taken to use only WCCS syntax and calls to ensure compatibility.