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Architecture - User Level OSS

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Note: The content on this page reflects the state of design of a Lustre feature at a particular point in time and may contain outdated information.

Summary Requirements

io_cli_fail if a Lustre client fails, and the OSS has partially executed an IO operation, it leaves the server file system in a reasonable state.
io_oss_fail if an OSS fails, a client will retry to complete partial IO operations and they will complete as if the OSS had not failed
io_no_copy for large IO transfers there will be no copy of data pages as is common in read/write system call implementation.
io_double_failure If the OSS and the client fail, allowing 0's in the file due to truncation is certainly permitted, even the possibility of bad data like in ext3 write back mode is probably acceptable.
io_llog_refinement Ideally with LAID llogging, a more complex method can be introduced that can undo the damage in the double failure case