[lttng-dev] [LTTNG-TOOLS PATCH] On-disk multiple tracefiles circular buffer - revisited

[Thibault, Daniel]

   Here are proposed semantics for the tracefile-size/tracefile-count enable-channel options (are they still planned for later inclusion in lttng-tools?):

-C, --tracefile-size SIZE
	This is a recent proposal (2013-Mar-08) that has yet to be added to the command.  Maximum size of each stored trace file (local or remote).  Default is zero, which means no limitation.  When set, each trace file is chopped into sequentially numbered segments of at most SIZE bytes each (e.g. "channel0_0" becomes "channel0_0_0", "channel0_0_1", etc.).  SIZE must be at least as large as the sub-buffer size.  The option is most useful if -W, --tracefile-count is also set.

-W, --tracefile-count NUM
	This is a recent proposal (2013-Mar-08) that has yet to be added to the command.  Maximum number of stored trace file chunks (local or remote).  Default is zero, which means no limitation.  When set, once the number of trace file segments reaches NUM the first segments are re-used (overwritten), creating an on-disc circular buffer of sorts.  The option has no effect unless the -C, --tracefile-size option is also set.

   Note that when -C is set but -W is not (or if -W is set to 1), this means the single trace file gets overwritten after each SIZE bytes.

Daniel U. Thibault
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