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Andy, I am trying to understand the olbd caching system. However, self-doubt persists and I wonder if you could help me. In the case of load-based selection (as opposed to round-robin), it looks like the following to me: 1. Each time a file is opened, the olbd manager makes a list (well, a mask) of servers that have the file (a primary) or that could stage the file. 2. It then checks the currently cached load information for each server from step 1 and takes the first one that isn't overloaded. 3. If the selected server doesn't already have the file, then the master tells it to stage the file and notes in the manager's cache that the file should be on this server in the future. 4. It then redirects the open request to the selected server. Now for the ignorant questions: If the manager olbd crashes, then the manager's cache of what files are already staged on a machine would be lost. When it restarts, does it rebuild that knowledge only by responding to requests to open files (at which point it may behave inefficiently by assuming that there are no primary servers for a file)? Or does it broadcast some directive to get information about which servers have the file already staged? If a server drops a staged file to make space for something else, does it also tell the manager so that the manager updates its cache of what files are where? Or does the central manager always direct what should be dropped (since it has more global knowledge about what is heavily replicated)? -- Gregory J. Sharp email: [log in to unmask] Wilson Synchrotron Laboratory url: http://www.lepp.cornell.edu/~gregor Dryden Rd ph: +1 607 255 4882 Ithaca, NY 14853 fax: +1 607 255 8062