> Does DFS take a huge performance hit due to its support of byte-level > locking?
Yes, there are a number of issues that come up with DCE/DFS. There is a token protocol between the fileserver and cache manager that provides for exclusive rights, synchronized read-writes, etc. The token meta-data is stored in memory in the fileserver instance and the cache-mgr instance. DFS fileservers could possibly require very large memory footprints in a big cell with frequent concurrent R/W access to files. Another phenomenon with DFS is that when a file server crashes and restarts, there is a "blackout" period in fileservice for some configured period of time ; usually 15 minutes.. This period is called token state recovery. During TSR, the file server sits and waits for cache managers who had prior been issues tokens to file to contact it to renew their tokens... This is how the fileserver rebuilds its list of clients locks after crash, and re-estabilishes the precedence on granting range order access to files... If a cache mgr is unable to reach the file server following the crash (i.e. network outage) - that cache manager simply becomes S.O.L. and simply loses whatever rights it held on access locks. Because the token protocol touches everything ; I doubt it would be possible to make DFS work in disconnected mode operation. There is a white paper on the DFS token protocol out there - I belive it was among the DCE 1.2.2 documentation tar ball. I havent touched DCE stuff in years though ; and dont intend to ever again. :) -- Jim _______________________________________________ OpenAFS-devel mailing list [EMAIL PROTECTED] https://lists.openafs.org/mailman/listinfo/openafs-devel
