Planning for High Availability
In mission-critical scenarios, any infrastructure must provide a high degree of availability for RFID systems to minimize data loss. To ensure high availability of your RFID infrastructure, and to preserve the integrity of your RFID applications, you can deploy BizTalk Server RFID on a cluster. This ensures that automatic failover takes place, and data loss is minimized, when a server does not respond or function normally due to critical errors (for example, hardware or software errors).
|Cluster support is only available in the BizTalk Server RFID Enterprise SKU or as part of BizTalk Server Enterprise edition.|
BizTalk Server RFID depends on Windows Clustering to provide high availability. Planning for high availability requires the infrastructure to be set up appropriately. For detailed setup instructions, refer to the white paper Installing and Running BizTalk Server RFID 2009 in a Windows Server 2008 Cluster, which you can download from http://go.microsoft.com/fwlink/?LinkId=157733.
|One of the key steps to make sure that the RFID cluster is set up correctly is to make sure that the RFID Service Account is set up as a domain account with administrative privileges in the nodes and has a roaming profile.Validation: To confirm that the user account that is used for the RFID Service Account (RSA) has a roaming profile, browse to the System Properties on each node in the cluster (click Start, right-click Computer, click Properties, and then click Advanced System Settings) and then click Settings for User Profiles. You must see that the account used for configuring the RFID Service Account is using a roaming profile.|
Windows Clustering continuously monitors the status of the hardware and software on the active server. In addition, BizTalk Server RFID implements a generic script resource (clusrfid.vbs) to continuously monitor the BizTalk RFID service on the active server. The script checks the state of the BizTalk RFID service that is surfaced to the cluster service. Failover occurs automatically when the service on the active server becomes unavailable. You can use the Microsoft Cluster Administrator to set the frequency at which the health of the BizTalk RFID service is checked.
When BizTalk Server RFID is deployed on a cluster, only one server runs the BizTalk RFID service. The server on which the service is running is considered to be the active server. When the active server fails, Windows Clustering automatically starts the service on the next available server in the cluster group. This ensures that loss of tag reads is minimized and the BizTalk Server RFID system is always running.
The following diagram shows BizTalk Server RFID in a clustered environment.
While clusters and disaster recovery both increase availability, a key difference between them is that clusters typically provide much faster recovery time than disaster recovery does. Therefore a solution built on server clusters or load balancing is commonly thought of as providing high availability as opposed to merely providing availability.
Disaster recovery allows you to resume operation of a failed system, but is typically a manual process and requires significantly more recovery time than a high-availability implementation. Therefore, a disaster recovery implementation provides availability but not high availability. You should employ high availability through server clusters, and consider disaster recovery, in a production BizTalk Server RFID environment. Disaster recovery is useful in scenarios where the cluster is down in the site but the devices are accessible from a remote location or from another computer in the same site. For more details, see Backup and Restore.