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DUCS archive copies are maintained at some, but not all, DUCS hosts. The selected list of hosts is specified at the top of the ducs_arch command file. The specified hosts should be those to which the DUCS and archive disks are physically connected. This avoids unnecessary network traffic within a cluster (a full copy of DUCS measures roughly 0.5 GB). If the disks are moved to different hosts within their cluster, the host list should be updated accordingly.
For each host, one or two models may be specified. This model specification is the model, alpha or vax, of code that is to be maintained by the specified host. This is not necessarily the same as the model of the host. Thus at SLAC, the host SLDA6 maintains code for both alpha and vax systems. At VU, the host VUPACB maintains code only for alpha systems.
The DUCS accounts on each of the hosts must have their .rhosts files set up correctly to allow remote shell logins from the DUCS account on the SLAC central unix VESTA machines. Specifically, the .rhosts files must contain the following lines:
Each of the hosts must have disk space for the archives located under the logical name disk$sld_arc_axp for alpha code or disk$sld_arc_vax for vax code. The archive disk should allow 2.5 GB for the entire alpha code archives and 1.5 GB for the entire vax code archives. This requirement allows the system to maintain the same set of archive copies at all hosts. The system will refuse to perform copies at any hosts if it does not measure sufficient available disk space at all hosts.
The actual work of measuring, copying, restoring and deleting files is performed by remote shell logins to the DUCS hosts. These logins pass a variety of parameters to the vms command file produtil:ducs_arch.com.
By centralizing many functions into this one command file, the system can achieve consistency in what files are excluded from measuring and copying actions. Examples of excluded files are the log files that DUCS maintains of its update activity. To change this list of what files are excluded from these actions, edit produtil:ducs_arch.com.