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156 lines
5.7 KiB
156 lines
5.7 KiB
What: /sys/block/<disk>/bcache/unregister |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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A write to this file causes the backing device or cache to be |
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unregistered. If a backing device had dirty data in the cache, |
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writeback mode is automatically disabled and all dirty data is |
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flushed before the device is unregistered. Caches unregister |
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all associated backing devices before unregistering themselves. |
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What: /sys/block/<disk>/bcache/clear_stats |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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Writing to this file resets all the statistics for the device. |
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What: /sys/block/<disk>/bcache/cache |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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For a backing device that has cache, a symlink to |
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the bcache/ dir of that cache. |
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What: /sys/block/<disk>/bcache/cache_hits |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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For backing devices: integer number of full cache hits, |
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counted per bio. A partial cache hit counts as a miss. |
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What: /sys/block/<disk>/bcache/cache_misses |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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For backing devices: integer number of cache misses. |
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What: /sys/block/<disk>/bcache/cache_hit_ratio |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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For backing devices: cache hits as a percentage. |
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What: /sys/block/<disk>/bcache/sequential_cutoff |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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For backing devices: Threshold past which sequential IO will |
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skip the cache. Read and written as bytes in human readable |
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units (i.e. echo 10M > sequntial_cutoff). |
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What: /sys/block/<disk>/bcache/bypassed |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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Sum of all reads and writes that have bypassed the cache (due |
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to the sequential cutoff). Expressed as bytes in human |
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readable units. |
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What: /sys/block/<disk>/bcache/writeback |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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For backing devices: When on, writeback caching is enabled and |
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writes will be buffered in the cache. When off, caching is in |
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writethrough mode; reads and writes will be added to the |
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cache but no write buffering will take place. |
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What: /sys/block/<disk>/bcache/writeback_running |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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For backing devices: when off, dirty data will not be written |
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from the cache to the backing device. The cache will still be |
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used to buffer writes until it is mostly full, at which point |
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writes transparently revert to writethrough mode. Intended only |
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for benchmarking/testing. |
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What: /sys/block/<disk>/bcache/writeback_delay |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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For backing devices: In writeback mode, when dirty data is |
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written to the cache and the cache held no dirty data for that |
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backing device, writeback from cache to backing device starts |
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after this delay, expressed as an integer number of seconds. |
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What: /sys/block/<disk>/bcache/writeback_percent |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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For backing devices: If nonzero, writeback from cache to |
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backing device only takes place when more than this percentage |
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of the cache is used, allowing more write coalescing to take |
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place and reducing total number of writes sent to the backing |
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device. Integer between 0 and 40. |
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What: /sys/block/<disk>/bcache/synchronous |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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For a cache, a boolean that allows synchronous mode to be |
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switched on and off. In synchronous mode all writes are ordered |
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such that the cache can reliably recover from unclean shutdown; |
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if disabled bcache will not generally wait for writes to |
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complete but if the cache is not shut down cleanly all data |
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will be discarded from the cache. Should not be turned off with |
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writeback caching enabled. |
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What: /sys/block/<disk>/bcache/discard |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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For a cache, a boolean allowing discard/TRIM to be turned off |
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or back on if the device supports it. |
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What: /sys/block/<disk>/bcache/bucket_size |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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For a cache, bucket size in human readable units, as set at |
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cache creation time; should match the erase block size of the |
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SSD for optimal performance. |
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What: /sys/block/<disk>/bcache/nbuckets |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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For a cache, the number of usable buckets. |
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What: /sys/block/<disk>/bcache/tree_depth |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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For a cache, height of the btree excluding leaf nodes (i.e. a |
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one node tree will have a depth of 0). |
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What: /sys/block/<disk>/bcache/btree_cache_size |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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Number of btree buckets/nodes that are currently cached in |
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memory; cache dynamically grows and shrinks in response to |
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memory pressure from the rest of the system. |
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What: /sys/block/<disk>/bcache/written |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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For a cache, total amount of data in human readable units |
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written to the cache, excluding all metadata. |
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What: /sys/block/<disk>/bcache/btree_written |
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Date: November 2010 |
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Contact: Kent Overstreet <[email protected]> |
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Description: |
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For a cache, sum of all btree writes in human readable units.
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