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i-Cluster Server 3.0

i-Cluster Server is the latest product development of i-Server by United Networks Inc., with years of expertise in development and support of Linux based solution.

i-Cluster improves overall customer satisfaction by providing load balance and high availability to web servers, mail servers, ftp servers, etc., through virtually any port.

Advanced Traffic Manager (ATM)
ATM performs the task to direct all incoming requests to cluster server which has the highest availability. The present version of ATM runs on Linux 2.2 or above. i-cluster Server running on Windows NT, 2000 server, 95/98 will be released soon. In case of down of ATM, backup ATM will take place and there is virtually no limitation on number of backup ATM stations. Backup ATM stations will synchronize with ATM station in customizable time of frequency.

Unlimited cluster nodes
No limitations on no. of cluster nodes and ATMs.

Platform independent cluster server
Cluster server can run on different platform, such as Linux, Windows 95/98/NT/2000, UNIX, Novell (running TCP/IP). Like ATM, there is virtually no limitation on number of cluster nodes. No software required for running as a cluster server.

Integrated Firewall Option
Prevents intrusion attack from external as well as internal network.

Virtually any port can cluster
No pre-defined requirement of service ports, meaning any port can cluster.

Adjustable Load Balancing Pattern
This feature allow administrators to put more load on servers with higher processing power and less load on servers with less processing power.

Stand-by servers
In case all cluster servers went down, stand-by server will assume service automatically. This stand-by server can be located anywhere connected via internet and contents might differ from cluster servers. This might be set up to, for instance display contingency messages in case of server failure.

Email notification
In case of failure of any server in the cluster network, local or remote, administrator will be notified by email or pager.

System Requirements
- Intel x86 architecture CPU, including Intel, AMD, and Cyrix models
- 32Mb RAM (128Mb recommended)
- 800Mb hard disk space
- 2 x PCI Ethernet Network adaptor
- 3.5-inch floppy drive

United Networks Inc.
www.unitednet.com.hk
enquiry@unitednet.com.hk

Comparing i-Cluster (ATM) with other clustering solutions

	IBM Cluster Systems Management for Linux (CSM),General Parallel File System (GPFS)	Kimberlite	ATM
Nodes	32 nodes	No limit	No limit
User Interface	GUI management interface.	Command and web management interface.	Command line and web management interface.
Node - Recovery	Admin may reset or power switch node at remote location. Limited to IBM hardware only.	User implement own power switch and UPS. Serial cable hooked up with peer systems allows peer monitoring and reset/power-cycle. (Called "Service Failover")	Not yet available. May implement techniques similar to Kimberlite.Recommendation: Node failover could be handled gracefully, with another server taking over the work of the failed server and making sure the integrity of data being processed on the failed node. Working nodes should recover failed node immediately. This is especially important on database servers. Be able to commit/reset/recover transactions or requests on failed node. Task could be simplified with the use of a distributed fault-tolerant filesystem (CODA).In order to minimize the disruption done to the Cluster/Node, ATM server monitoring the failed node should attempt to restart only the failed service, resorting to the entire server when this step fails.
Node - Monitoring	Centralised control from Server (as oppose to Node). Uses a common storage area for keeping node heartbeat and status information.	No centralized control. Uses peer monitoring among Nodes insteadUses common storage to keep node status. Peers probe each other as well as actively updating own status in shared memory (Quorum). A node is deemed failed when it fails either response to a statue probe, or fails to write status to shared memory.	Centralised control. Server (or Backup Server) keeps track of the node status (Heartbeat Ping). Cluster nodes therefore are relieved from the task of probing each other. Thus reducing traffic on the network.Heartbeat ping implemented using ICMP. Implementing Node Service monitoring, which defines the specific port number to monitor in a Node.
Node - Maintenance	Administration and maintenance of node can be done remotely. Also has an option of combining output from multiple nodes.		Because ATM do not use client program on Node, obtaining accurate performance figures and remotely configuring nodes may be difficult. This can be resolve through other means such as providing telnet or remote configuration program.On the plus side. By not placing a client on the Node this practice simplifies the system design and reduce the amount of traffic.
Server - Configuration	Only centralized control and one form of cluster set up. One server per cluster, containing multiple nodes.	Can be implemented in several configurations. Such as active peer monitoring configuration where each Node runs different services and each Node keeps track of other and services. Or the primary/backup configuration where when a primary Node fails, the secondary/backup Node becomes active and automatically takes over the service.	Users centralized monitoring with backup node when primary servers failed (called "fallback", or be implemented.Could make use a voting system between ATM servers and a shared common area (quorum) when one server fails. Also, to prevent the primary server becoming a bottleneck a DNS rotation scheme can be implemented to make proper use of the backup ATM servers.
Server - Monitoring	Unknown	Uses heartbeat ping between peer servers/nodes, also use Quorum to detect non-behaving servers.	ATM servers use peer monitoring ATM primary and backup servers. Data synchronization also happens at this point.
Error Logging	Logging/Output to a common output (Distributed Shell)	Uses syslog with severity level	Log file per Node and each ATM server.
Scheduling & Load Balancing	No information	No information	Task scheduling in a weighted round-robin fashion. When a certain node fails request is automatically passed on to the next available node, with regards to the node weighting/priority.
OS Implementation	Linux, AIX	Node systems using same OS (linux)	Node systems are free to use any OS. OS independent as no client software on a Node are necessary.
File System & Storage	Can deploy propriety file system: General Parallel File System (GPFS). Features: Block level locking, Data Stripping along several drives.	No filesystem information. Hardware recommendation based on SCSI RAID drives with partition locking.	SAN (Hardware solution). Recommended also making CODA filesystem (Software solution) part of the software, which is widely available and the CODA driver is part of a regular kernel. However, simultaneous access (bad) may need some work.