! ! !
*GE,!the!GE!Monogram,!Centricity,!and!imagination!at!work!are!trademarks!of!the!General!Electric! Company.!
GE Healthcare Centricity* PACS-IW
on VMware
®
vSphere or VMware Virtual
Infrastructure
September 2011
Table of Contents
Introduction ... 1
!
VMware and Centricity PACS-IW Overview ... 1
!
Centricity PACS-IW Overview ... 1
!
VMware vSphere or VMware Virtual Infrastructure ... 2
!
GE Centricity PACS-IW Architecture and Deployment Strategy ... 3
!
Testing Process and Results ... 5
!
Testing Methodology and Overview ... 6
!
Hardware and Software Configuration ... 6
!
Virtual Machine Configuration ... 7
!
Workload Used ... 8
!
ESX Host Utilization ... 10
!
Additional Testing ... 11
!
VMotion ... 12
!
Deployment Best Practices ... 13
!
Reference Architecture ... 14
!
Conclusions ... 14
!
Introduction
This document provides direction to those interested in running Centricity PACS-IW on VMware® vSphere™ 4. It provides basic guidance on the architecture of GE Centricity PACS-IW, as well as the value of utilizing the VMware platform. The results of recent testing done jointly by VMware and GE Healthcare are covered, where the performance and functionality of Centricity PACS-IW on VMware virtual infrastructure are characterized. Finally, some best practices for utilizing the two product sets together in GE datacenter are outlined.
VMware and Centricity PACS-IW Overview
Centricity PACS-IW Overview
PACS-IW is a medical software system that is intended for acquisition and storage of medical images and other information objects generated by the acquisition equipment (modalities) as well as other devices (post-processing workstations). It allows multiple users to remotely access the images it stores, from compatible computers on a network, for the purpose of manipulation, diagnostic interpretation and post-diagnostic review of the images and other objects it stores.
Both the client and server software of Centricity PACS-IW are only for use with off the shelf hardware technology that meets defined minimum specifications.
Centricity PACS-IW shall operate within operating environment that meets defined minimum specifications. The system allows users various methods of exporting information, including the original information it acquires as well as user work results. This includes sending images and other objects to the external systems over the network utilizing the DICOM protocol, saving them on CD in DICOM and Proprietary formats, printing of Key Images onto DICOM and Windows printers, printing Notes, Reports and other information on Windows printers.
Centricity PACS-IW provides integration capabilities with other types of information systems in the
Healthcare Enterprise (HIS, RIS, EMR, dictation and voice recognition systems), by accepting patient, order and report information from such systems via HL7 protocol, and sending notifications to them about arrival of new studies, change of study status or creation of notes within PACS-IW. PACS-IW uses proprietary web-services based protocol for similar by-directional communication with RIS-IW.
Centricity PACS-IW supports desktop integration with various Information systems to invoke PACS-IW viewer for display of a study identified by the external system, via different mechanisms and different degree of control of the viewer.
Centricity PACS-IW supports desktop integration with various Information systems to invoke modules of such system for display of supplementary information associated with the study selected within PACS-IW. The information may pertain to the specific study, order/visit or patient. The desktop integration can also be employed to perform certain operations (such as dictation of the diagnostic report) within external system using information provided by the PACS-IW (for example, accession number of an order).
PACS-IW supports desktop integration with various advanced processing or advanced visualization software packages to invoke them for the purpose of additional processing of imaging information stored within PACS-IW, and subsequent storage of resulting DICOM objects within Centricity PACS-IW.
The main categories of users to utilize the PACS-IW, either standalone or in integration with various information systems and advance are:
purpose of rendering diagnosis and documenting it in the form of notes, reports, key images, annotations and other objects as may be necessary by the workflow and procedural requirements of particular Healthcare Enterprise
• Technologist – uses PACS-IW in a course of acquisition of imaging studies, quality control and creation
of additional clinical evidence for further use by Radiologist in interpretation process.
• Clinician – uses PACS-IW to review results of interpretation by Radiologist and to determine further
steps in clinical care, such as surgery or biopsy. May create additional clinical evidence for further use by Radiologists, other Clinicians and Referring Physicians.
• Referring Physician – uses PACS-IW or a CD/DVD generated by PACS-IW to review results of
interpretation by Radiologist. Referring physicians often access PACS indirectly through URL- or API-based launching of the viewer.
• Clinical Admin – clinically knowledgeable administrative user, such as PACS administrator or chief
Technologist, who performs tasks such as splitting and merging studies, exception resolution, etc.
• Resident - a radiological resident who uses PACS-IW to create preliminary report which has to be later
reviewed and signed by the attending radiologist
• ED Physician – a physician in the Emergency Department who can create a note with initial
impressions of a study, which then has to be reviewed by Radiologist who creates final report
• Clinical Staff – users in and outside the department (nurses, film library clerks, front desk staff, etc.)
who access and modify patient records by adding notes, scanning documents, viewing, printing and exporting studies.
• System Administrator – Manages system configuration and maintains it for the purpose of achieving
optimal performance and reliability.
The PACS-IW is not intended to be used by Patients.
VMware vSphere or VMware Virtual Infrastructure
VMware’s leading virtualization solutions provide multiple benefits to IT administrators and users. VMware virtualization creates a layer of abstraction between the resources required by an application and operating system, and the underlying hardware that provides those resources. A summary of the value of this abstraction layer includes the following:
• Consolidation: VMware technology allows multiple application servers to be consolidated onto one
physical server, with little or no decrease in overall performance.
• Ease of Provisioning: VMware virtualization encapsulates an application into an image that can be
duplicated or moved, greatly reducing the cost of application provisioning and deployment.
• Manageability: Virtual machines may be moved from server to server with no downtime using VMware®
VMotion™, which simplifies common operations like hardware maintenance and reduces planned downtime
• Availability: Unplanned downtime can be reduced and higher service levels can be provided to an
application. Provided the environment is configured correctly and there is available capacity on remaining hosts VMware® High Availability (HA) ensures that in the case of an unplanned hardware failure, any affected virtual machines are restarted on another host in a VMware cluster
Figure 1. VMware vSphere Virtual Infrastructure
GE Centricity PACS-IW Architecture and Deployment
Strategy
GE Centricity PACS-IW is a software system that is supported in various deployment models. The following description applies to the GE Centricity PACS-IW version 3.7.3.x versions. The software incorporates multiple component subsystems that can run on the same, or on different Windows Server 2003 instances. The basic components are:
• Webserver: The webserver is the basic mode of access by users and administrators to the application
and runs on TomCat webserver. Access protocols must include SSL/HTTPS and standard HTTP. Tomcat is supported for use with Centricity PACS-IW on Microsoft Windows Server 2003 running in 32-bit mode.
• DICOM Server: The DICOM server incorporates DICOM 3.0 standard toolkits and enables the
application to process standard inbound DICOM transmissions over TCP/IP, as well as transmitting outbound DICOM over TCP/IP. This component is supported on Microsoft Windows Server 2003 running in 32-bit mode.
• Storage Controller (Image Storage): The Storage Controller is part of the Centricity-IW application stack
that enables the PACS to read and write image data to the server filesystem. The Storage Controller also manages the transmission of outbound HL-7/Study Status Change Notification (SCN) messages to 3rd party applications such as RIS or EMR systems. The Storage Controller is supported on Microsoft Windows Server 2003 running in 32-bit mode.
• HL-7 Server: The HL-7 server is part of the application stack that enables the PACS to receive and
process inbound HL-7 messages. The HL-7 Server is supported on Microsoft Windows Server 2003 running in 32-bit mode.
• Viewer: The Viewer component is an application that is deployed to user workstations via Active-X
automatically the first time a user logs into the application from the workstation. User interaction to the server is accomplished via the Microsoft Internet Explorer web browser, whereby the user can configure basic profile settings and view a “study list”. When the user opens a specific study or studies, images are launched through the viewer application. All access to the server is accomplished via TCP/IP over HTTP and HTTPS/SSL. Web browser access is only supported on Microsoft Internet Explorer version 6.x, 7.x or 8x. The Viewer is supported on a workstation running Microsoft Windows XP, Vista or 7 x32.
• Other Application Stack Components: The application stack incorporates multiple other components not
listed above and controls basic how the application behaves, authenticates users (either internally or via LDAP integration), manages user sessions, manages licensing, moves image data to near-line or offline storage, serves image data through the web server, and communicates to the database. The application stack components are supported on Windows Server 2003 running in 32-bit mode.
• Database: The Centricity PACS-IW database instance (actually three databases) is managed by
Microsoft SQL Server 2005. The database manages all system user profiles, as well as all study data, other than the physical images which are stored on the filesystem by the Storage Controller. The Database component may run on Microsoft SQL Server 2005 in either 32-bit or 64-bit mode, running on Microsoft Windows Server 2003 running in either 32-bit or 64-bit mode.
The above listed components may run on one or more server configurations, with the various basic environment options:
• Stand Alone or Single Server configuration: A single Microsoft Windows Server 2003 server running in
32-bit mode may run all sub-system components, including the database which must run on Microsoft SQL Server 2005 in 32-bit mode. This installation is meant for low volume environments, usually less than 25 thousand studies per year.
• Multi-Server Environment: For larger installations, sub-system components may be separated onto
multiple servers. The options all incorporate a separate database server running Microsoft Windows Server 2003 and Microsoft SQL Server 2005, which both may be run in 64-bit mode to enable more efficient addressing. Additionally, a “Controller” server must be deployed, and in some cases, “Node” servers (one or more) may be deployed as an option for the purpose of increasing system processing power for inbound DICOM transmission, or for enabling user access to a local webserver to improve performance on Viewer-to-Server communications. Additionally, a “Business Continuity Server” may be deployed which essentially is a Stand Alone server with all the components running on it, independent of the production environment, to act as a cold standby to the production environment. The actual physical database may be backed up routinely to the Business Continuity Server. All of these components are defined as follows:
o Controller: Server that controls the primary application components and will always run the Storage Controller, DICOM Server, Webserver, and other used application
components other than the database. Due to the subsystem components deployed on the Controller, it must be run on Microsoft Windows Server 2003 in 32-bit mode. The
Controller is attached to the primary study archive storage, which may be stored on a SAN or DAS. The Controller may be clustered for high availability.
o Node: The Node runs a subset of subsystem components and does not manage the primary study archive storage. Nodes are optional, but may be deployed in higher volume configurations to improve performance. Nodes will usually include the DICOM Server, Storage Controller, and in some cases, a Webserver. The Node may be used to process inbound DICOM to offload work from the Controller, and may also be used as a remote Webserver and short-term study storage device to allow remote facilities quick access to study data. Nodes are supported on Microsoft Windows Server 2003 in 32-bit mode, and may be clustered for high availability.
o Database: The Database server manages the Centricity PACS-IW database and runs on Microsoft SQL Server 2005 on Microsoft Windows Server 2003, both run in either 32-bit or 64-bit mode. The database server may be clustered for high availability.
provides for each of the remote sites to be equipped, in addition to the store/forward server, with the standalone single server instance of PACS-IW (Standby Server) and the DICOM Gateway that directs incoming studies to BOTH store/forward server and the Standby server. The system installed on a Standby Server is kept ready for all users of the Main system via replication of definitional data to all Standby Servers known to the system.
The following diagram shows a high level view of a common configuration, deployed with a Node, Controller, and Database.
Figure 2. GE Centricity PACS-IW Solution Architecture Design
Testing Process and Results
To characterize the performance of GE Centricity PACS-IW on VMware Infrastructure performance tests were carried out jointly by VMware and GE. The configuration tested and the results for Controller are summarized below.
Using LoadRunner to emulate a typical PACS-IW deployment, we ran test cases at the following vusers The response time index has been calculated for a 3117 image CT study with load evenly distributed across all the 5 LoadRunner Agents
TEST CASE
(VUSERS) RESPONSE TIME INDEX (SEC) CPU UTILIZATION <CONTROLLER> MEMORY UTILIZATION <CONTROLLER> DISK UTILIZATION <CONTROLLER>
No Load 130 6.1 % 1523.3 MB 646.43 10 144 8.3 % 1639.3 MB 825.11 20 151 10.2 % 1667.2 MB 1197.93 40 176 12.0 % 1966.3 MB 1311.12 80 161 12.97 % 1982.1 MB 1454.49 160 347 14.1 % 2072.2 MB 1604.25
Testing Methodology and Overview
The primary objectives of testing were to determine GE PACS-IW performance characteristics and show that GE PACS-IW can scale linearly and be run more resiliently on VMware virtual infrastructure. (The goal was also to ensure that customers could successfully deploy their mission-critical PACS-IW applications in the same virtual environments.) Testing also validated the operation of VMware features including vMotion, VMware DRS, VMware Fault Tolerance (FT), and VMware HA with PACS-IW deployments in a virtual environment.
Hardware and Software Configuration
The following diagram provides details about the setup of ESX host servers and virtual machines used to perform the tests described earlier.
Figure 3. Hardware Configuration for GE Centricity PACS-IW Testing
Hardware and System Host Configuration
The following table describes the configuration of ESX host servers and storage in the GE test configurations.
Table 2. ESX Host Hardware
H A R D W A R E C O N F I G U R A T I O N
Server Two HP ProLiant DL 360 G7 (Nehalem) Servers. Each server is equipped with:
• 2.8 GHz dual quad-core Intel Xeon E5560 • 48 GB RAM Storage EMC • Clarion CX4, RAID 10 • FC 4Gbps • 15 disks, 133 GB each
Installed Software
Table 2 lists the software used in the GE solution.
Table 3. Software Installed for GE Solution
Installed S oftw are
VMware VMware vSphere 4.1, vCenter Server 4.1, ESX® 4.1 Microsoft Microsoft SQL Server 2005 x64
GE GE Centricity PACS-IW, V3.7.3
Virtual Machine Configuration
The following table describes the configuration of virtual machines running on ESX host servers in the GE Centricity PACS-IW test configurations
Table 4. Virtual Machine Configuration
V I R T U A L M A C H I N E H A R D W A R E C O N F I G U R A T I O N
One PACS-IW Controller
• 4 vCPUs • 4 GB memory • 1 Ethernet card
• 50 GB (OS Disk) + 500 GB(Data Disk) storage • vmdk for OS disk and RDM for data disk Three PACS-IW Nodes • 4 vCPU
• 4 GB memory • 1 Ethernet card
• vmdk only
P H Y S I C A L M A C H I N E H A R D W A R E C O N F I G U R A T I O N
Microsoft SQL Server • HP ProLiant DL 360 G7 (Nehalem) • 12 CPUs
• 24 GB RAM Five Load Runner Agents
• HP ProLiant DL 370G6 (Nehalem) • 16 CPUs
• 24 GB memory
Workload Used
For GE PACS-IW performance testing, the workload driver is LoadRunner. The PACS-IW Viewer application is used to generate load on the LoadRunner Agents and increasing the number of concurrent vusers increases the requests for study load on the GE PACS-IW Controller and nodes. The number of vusers is equally divided among all the five LoadRunner Agent and the PACS-IW performance is measured through a client machine by opening another set of studies during the tests, while all concurrent users are running and generating load on the system. Standard radiology image sets were used consisting of CT, MR, MG, US and CR.
Results Observed
The graphs below show Average and Max CPU utilizations, and memory consumptions for No Load, 10, 20, 40, 80 and 160 vusers load Tests.
The results show that the virtual machine configuration used in the tests adequately handles load for various workloads. As shown in the CPU and MEM columns of the table, GE PACS-IW Controller Virtual machine utilizes 14% of the CPU resources, with two vCPUs in the virtual machine, and uses an average of 2072 MB RAM. Other columns in the table provide data on network traffic, I/O rates (CMD/sec is the number of I/O operations done each second), the latency to disk observed from the device and guest levels (DAVG and GAVG),
Table 3. 160 vUser VM Utilization
VM CPU Memory Network Disk Latency(ms)
(%) (mb) Packets/sec I/O sec Read Write
Avg Ma
x Ready Avg Max Recd Txmitted Avg Max Avg Max Avg Max (Avg/Max) VMNode1 1.2 5.6 1 0.02/0.035 159.74 245.76 217.69 135.28 0.65 7.015 0.37 3.5 3.045 15.60 VMNode2 1.1 5.2 7 0.025/0.065 1142.3 2048 116.82 74.015 0.585 4.945 0 0.11 3.105 14.45 VMNode3 1.2 5.7 3 0.025/0.056 162.5 225.28 206.38 128.17 0.625 5.73 0.02 2.865 3.02 12.95 VMControll er 14.1 39.1 0.0125/0.03 2072.3 2575.7 8 1824. 2301.95 1604.2 2878.115 3.47 6.06 12.905 22.1
Additional Testing
High Availability
Key features of HA are Automatic detection of server failures, Automate the monitoring of physical server availability. HA detects server failures and initiates the virtual machine restart without any human intervention. Resource checks to ensure that capacity is always available in order to restart all virtual machines affected by server failure. HA continuously monitors capacity utilization and “reserves” spare capacity to be able to restart virtual machines. The HA cluster feature allows the virtual machines running on ESX Server systems to automatically recover from host failures. When a host becomes unavailable, all associated virtual machines are immediately restarted on other hosts.
.
High Availability Test
To examine how Controller and Nodes could leverage VMware HA, the test arranged PACS-IW Controller virtual machine on one host (ESX host-A) and the PACS-IW nodes on the second host (ESX host-B) of a two node cluster. The physical host for ESX host-A was then rebooted. VMware vSphere detected the
interruption and automatically restarted the Controller virtual machine on ESX host-B.
VMotion
VMotion enables the live migration of running virtual machines from one physical server to another, with zero downtime, continuous service availability, and complete transaction integrity. This capability makes hardware maintenance possible at any time of the day and does not require clustering or redundant servers. VMotion makes it possible to move online workloads as required, from one ESX host machine to another, in order to maintain service levels and performance. The scope of this test was to check the migration of the AppServer virtual machine.
vMotion Test
With the LoadRunner test in progress and Controller/ Nodes running on separate ESX hosts, the vMotion test was initiated to migration one of the Node to ESX host-A and the controller to ESX host-B. VMotion migration was completed successfully, with no failures, indicating that user activity could continue successfully during any VMotion events.
Deployment Best Practices
Here are some of the best practices derived from configuration and testing of the xCP application in a VMware virtual infrastructure environment
• It is recommended to use Intel based Nehalem or AMD based Shanghai processors which have the
Hardware-Assist capabilities which help in memory management operations.
• While using Intel based systems, ensure that the BIOS settings enable Hyperthreading, VT, and EPT
options on all ESX hosts.
• Use Eager zeroed disks for better IO performance. This can be done using the VMware vmkfstools
command:
vmkfstools –w abc.vmdk
• To decrease disk latency it is recommended to use Fiber Channel Adapters and configure proper RAID
configuration with sufficient spindles.
• Install VMware tools on the VM’s. The VMware Tools package provides support required for shared
folders and for drag and drop operations. Other tools in the package support synchronization of time in the guest operating system with time on the host, automatic grabbing and releasing of the mouse cursor, copying and pasting between guest and host, and improved mouse performance in some guest operating systems.
• Consider using server-class network interface cards (NICs) for the best performance and configure
paravirtualized vmxnet3 adapters for better network throughput.
• Ensure that the Service Console/VMkernel and VM’s are configured on separate NICs.
• Disconnect or disable unused or unnecessary physical hardware devices, such as:
COM ports LPT ports USB controllers Floppy drives
Optical drives (that is, CD or DVD drives)
The above will help free up interrupt resources, traditionally, some devices, such as USB controllers, operate on a polling scheme that consumes extra CPU resources. Lastly, some PCI devices reserve blocks of memory, making that memory unavailable to ESX.
Reference Architecture
This section provides an overview how one typically deploys GE Centricity PACS-IW on vSphere in different scenarios, for example, small and medium-sized deployments versus Enterprise environments.
The GE Centricity PACS-IW tests were run for the Extra Large Enterprise deployment. The remaining configurations are not tested during the validation and are based on interpolation of data collected during the Extra Large Enterprise tests.
Enterprise (vCPU/Memory) VM Small 75,000 – 150,000 Medium 150,001 – 240,000 Large 240,001 – 330,000 Extra Large 330,001 – 420,000
Controller 4vcpu/4GB RAM 4vcpu/4GB RAM 4vcpu/4GB RAM 4vcpu/4GB RAM
SQL DB Dual 6-core CPU/12
GB
Dual 6-core CPU/24 GB
4 6-core CPU/24 GB 4 6-core CPU/32 GB
DR/Cold Spare
4vcpu/4GB RAM 4vcpu/4GB RAM 4vcpu/4GB RAM 4vcpu/4GB RAM
Node1 4vcpu/4GB RAM 4vcpu/4GB RAM 4vcpu/4GB RAM
Node2 4vcpu/4GB RAM 4vcpu/4GB RAM
Node3 4vcpu/4GB RAM
Total 8vpu/ 8GB RAM 12vpu/ 12GB RAM 16vpu/ 16GB RAM 20vpu/ 20GB RAM
ESX Hosts Recommend
physical host with min 2 x quad core procs and 12GB RAM
Recommend physical host with min 2 x hex core procs and 12GB RAM
Recommend 2 x physical hosts with min 2 x quad core procs and 8GB RAM each
Recommend 2 x physical hosts with min 2 x quad core procs and 16GB RAM each
Conclusions
Overall, testing results show that running GE Centricity PACS-IW on VMware Infrastructure performs well. Furthermore, it has potential to reduce cost, increase service levels and simplify the manageability of the application.
Resources
Customers can find more information about VMware and GE Centricity PACS-IW products via the links listed below:
Customers can find more information about VMware and GE products via the links listed below. VMware Resources
• VMware official website:
http://www.vmware.com/
• VMware Infrastructure 3 and vSphere 4 product Web site:
http://www.vmware.com/products/datacenter-virtualization.html
• VMware download Web site:
https://www.vmware.com/download/
• VMware support Web site:
http://www.vmware.com/vmtn/
• VMware Performance Tuning Paper:
http://www.vmware.com/pdf/Perf_Best_Practices_vSphere4.1.pdf
• System Compatibility Guide for a complete list of compatible hardware:
http://www.vmware.com/resources/compatibility/search.php
GE Resources
• GE Web site:
