BTR (Buffer Turnover Rate)

Buffer Turnover Rate, one of Art Kagel's buffer-cache metrics: how many times per hour the buffer cache is replaced, calculated as ((pagreads + bufwrites) / number of buffers) / hours since the statistics were zeroed (onstat -p). About 10 or less means the cache turns over no more than once every six minutes; a consistently higher figure suggests too few buffers. On insert-heavy systems it can read high while performance is fine, so check BTR2 (which counts actual disk writes instead of bufwrites) before adding buffers.

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