Frequently Asked Questions
What is the difference between array computing and cluster computing?
There are significant differences between Array and Cluster computing architectures.
Cluster computing is a model of many wholly-independent servers loosely coordinating their operations. A cluster application (or cluster service) is multiple application instances loosely coordinating their operations amongst the participating nodes of the cluster computing system.
The RAIS Array is a computing model for consolidating a collection of independent computing elements into single virtual computers. Using sophisticated virtualization technology, all of the independent resources of each server node (i.e. CPUs, memory, etc) are aggregated together to create a single large virtual computer system.
Attached servers no longer operate independently but instead function as processing elements of virtual system. If any failure occurs within the application, infrastructure or hardware, application tasks are automatically transferred to working elements in the array before any application loss can occur.
What is meant by Single System Image?
Once attached to a controller, individual servers may be associated into at least one virtual computer. This virtual computer portrays all the characteristics of a single system, including processor speed, memory, among other attributes . By compartmenting all server hardware, operating system, and middleware infrastructure into one single entity, RAIS isolates applications from the rest of the IT environment onto a tightly controlled, but easily managed and configured virtual system.
Is RAIS a virtualization technology?
Yes. RAIS is a server virtualization technology. It creates a virtual SMP environment that is intended to optimize the performance and reliability of all enterprise applications. It is designed to complement other virtualization technologies including solutions from Citrix® and VMWare®.
Like solutions from these vendors, RAIS uses Virtual Appliance packaging to deliver its solutions.
How does RAIS array performance scale when adding new servers?
Adding new servers to a server array adds the CPU and memory of the newly attached node to the aggregate CPU and memory resources of the RAIS array. Applications operating on a RAIS array can access these new resources immediately and transparently.
Are there any specific requirements for servers to be used in a RAIS array?
No. Any vendor’s make or model of standard x86 64-bit servers can operate in a RAIS array. Any combination of x86 servers can be combined into RAIS arrays. Waratek does not sell special RAIS servers.
Can I run any software on a RAIS array?
The initial RAIS Virtual Appliance is designed to provide fault tolerance for the Tomcat-based, Java application Platform. Any Java application will operate on the RAIS array automatically and transparently.
Do I need a special development kit to develop new software for a RAIS array?
RAIS is designed to run supported x86 applications without modification.
No special development tools or APIs are required to operate applications on a RAIS array.
How much hard drive space is required per server in a RAIS Array?
RAIS doesn’t require local hard disks or other direct-attached storage devices. If present, they remain untouched.
Do I need to install operating systems?
No. If individual OS’s are currently installed on local hard drives, they will not be used or modified in any way.
What prerequisite software must be installed on each node of a RAIS array?
Nothing. Each attached server becomes a stateless processing element of the RAIS Array.
How do I access my file system from a RAIS array?
In normal configurations, server arrays rely on Storage Area Networks (SAN) or Network Attached Storage (NAS) to provide the file system(s) for the array
How do I administer RAIS?
A RAIS array is administered through the RAIS Controller appliance’s administration interface, a web-based management console. From this management interface, servers and virtual computers can be configured, combined into system images, removed, resized, etc.
