Building A Common Server Oper ating Environment In all cases, however, full synchronization should be performed every month or quarter to ensure all core areas of the common server environment are identical. Full synchronization also can be used when a force synchronize is necessary. For example, if a local administrator frequently makes changes to the core areas of a server without testing or informing the central IS. The Process To give you a better idea of the synchronization process flow, see "Common Server Operating Environment Synchronization Process" above. In this model, the master server keeps the most up-to-date image of a server in the common server operating environment. It is essentially a fully functional duplicate with all applications installed, but should not be used to serve u sers--it must retain the integrity of a core system and common application files. The master server also can be used as a staging server to distribute to your common operating server environment. Therefore, the master server should be backed up before changes are applied. As its name implies, the test server is used to test new software, drivers and configurations. It may be used by many different groups within your organization. Therefore, it's essential that before testing changes to a common server operating environment, you completely rebuild the test server with a fresh image from the master server. Once changes have been tested, verified and the results documented in the pre- and postreplication procedures, they should be integrated into the master server. The prereplication procedure is sent to the remote site LAN administrator before changes are pushed. Communication from the master server to remote servers is one way; updates should not be propagated from the remote site servers to the master server. The Incremental Synchronization In most CSO environments, an incremental synchronization may be suitable because patches, bug fixes and new drivers usually retain the same name--with different dates and ti me stamps. A simple incremental synchronization can be implemented with a minimal amount of programming through the use of readily available shareware software, such as PKZIP, PKUNZIP and some knowledge of batch commands programming. Because of PKUNZIP's ability to refresh only existing files and copy only new files, you can implement the incremental synchronization program by first zipping the core area directories with the recursive subdirectories and store path name options (PKZIP -R -P). After delivery, a simple unzipping of the compressed file is all that's required. Be sure to run PKUNZIP with the restore/create directory and extract only newer files options (PKUNZIP-N-D). Additionally, you will need to change the network file attribute to read and write because PKZIP do es not handle network file attributes properly. To restore the proper attributes on the remote server, you need to identify network file attributes for every file stored on the master server and keep the records for the reconstruction later. Similarly, you will need to change the network file attributes of files in the core areas of the remote server so that PKUNZIP can refresh the files properly. A record of changes can be created by piping the process to a text file. Finally, the WAITEVNT utility can be used to schedule the update during a chosen server maintenance window. The Full Synchronization Remember, full synchronization requires not only deleting files in the core areas, which are not in the reference updated list, but also refreshing existing and copying new files. A more efficient way to implement full synchronization is to utilize a more capable programming language with a large set of built-in functions, such as the ability to compare file dates, times and sizes. Typically, a f ull synchronization is performed after an incremental synchronization. The incremental synchronization is achieved by comparing each file in the target directory with files in the reference directory. If there is no match, files in the target directory are no longer needed and are deleted. Thach Vo is a network software analyst with a large energy corporation located in the San Francisco Bay area.

The Road to Fast Ethernet Networks by Joel Conover Updated Februayr 7, 1997