Contract # GS00T01AHD0002 

Proposal to Add Federal Telecommunications Service   Long Distance (FTS LD) 

component that can automatically take over in the event of failure. (NOTE: AT&T 

Enterprise Hosting Services only supports two (2) servers in a database cluster.) 

Clustering succeeds through the shared use of a disk array. Two identically 

configured systems have direct access to an external mirrored disk array. Only one 

system is actually `active' at any one time: the other system is running and ready to 

take over in the event of hardware or software failure on the live system; it is 

considered to be the `passive' system. This kind of configuration is commonly 

referred to as active/passive. Each server checks the uptime of the other via 

 heartbeats . If the active server is halted for maintenance purposes, or due to a 

system crash, the passive machine will take over and provide the database service. 

This process of one server automatically shifting workload to another is called  fail 

over . 

AT&T Enterprise Hosting Services manages two (2) two node active passive fail 

over clustering services, the Oracle/UNIX Clustering Service and the MS 

SQL/Windows 2000 Clustering Service.  

6.7.11.2.1  Clustering Services   MS SQL/Windows 2000 

AT&T has integrated the MS Windows 2000 reference system with Compaq's 

established clustering solution to provide a variety of high availability server systems. 

MS SQL Server runs very effectively in a clustered environment to provide an overall 

secure, powerful and highly available database server. 

AT&T manages three MS SQL/Windows 2000 clustering bundles available: low end, 

mid level, and high end bundles. Each bundle includes two Compaq ProLiant 

servers, one Compaq RA 4100 External Storage Array and one MS SQL Enterprise 

Server 7.0 License (application will be installed on both servers).  

Use or disclosure of data contained on this sheet is subject to the restriction on the title page of this proposal. 

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