Commit | Line | Data |
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cafe5635 KO |
1 | What: /sys/block/<disk>/bcache/unregister |
2 | Date: November 2010 | |
3 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
4 | Description: | |
5 | A write to this file causes the backing device or cache to be | |
6 | unregistered. If a backing device had dirty data in the cache, | |
7 | writeback mode is automatically disabled and all dirty data is | |
8 | flushed before the device is unregistered. Caches unregister | |
9 | all associated backing devices before unregistering themselves. | |
10 | ||
11 | What: /sys/block/<disk>/bcache/clear_stats | |
12 | Date: November 2010 | |
13 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
14 | Description: | |
15 | Writing to this file resets all the statistics for the device. | |
16 | ||
17 | What: /sys/block/<disk>/bcache/cache | |
18 | Date: November 2010 | |
19 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
20 | Description: | |
21 | For a backing device that has cache, a symlink to | |
22 | the bcache/ dir of that cache. | |
23 | ||
24 | What: /sys/block/<disk>/bcache/cache_hits | |
25 | Date: November 2010 | |
26 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
27 | Description: | |
28 | For backing devices: integer number of full cache hits, | |
29 | counted per bio. A partial cache hit counts as a miss. | |
30 | ||
31 | What: /sys/block/<disk>/bcache/cache_misses | |
32 | Date: November 2010 | |
33 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
34 | Description: | |
35 | For backing devices: integer number of cache misses. | |
36 | ||
37 | What: /sys/block/<disk>/bcache/cache_hit_ratio | |
38 | Date: November 2010 | |
39 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
40 | Description: | |
41 | For backing devices: cache hits as a percentage. | |
42 | ||
43 | What: /sys/block/<disk>/bcache/sequential_cutoff | |
44 | Date: November 2010 | |
45 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
46 | Description: | |
47 | For backing devices: Threshold past which sequential IO will | |
48 | skip the cache. Read and written as bytes in human readable | |
49 | units (i.e. echo 10M > sequntial_cutoff). | |
50 | ||
51 | What: /sys/block/<disk>/bcache/bypassed | |
52 | Date: November 2010 | |
53 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
54 | Description: | |
55 | Sum of all reads and writes that have bypassed the cache (due | |
56 | to the sequential cutoff). Expressed as bytes in human | |
57 | readable units. | |
58 | ||
59 | What: /sys/block/<disk>/bcache/writeback | |
60 | Date: November 2010 | |
61 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
62 | Description: | |
63 | For backing devices: When on, writeback caching is enabled and | |
64 | writes will be buffered in the cache. When off, caching is in | |
65 | writethrough mode; reads and writes will be added to the | |
66 | cache but no write buffering will take place. | |
67 | ||
68 | What: /sys/block/<disk>/bcache/writeback_running | |
69 | Date: November 2010 | |
70 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
71 | Description: | |
72 | For backing devices: when off, dirty data will not be written | |
73 | from the cache to the backing device. The cache will still be | |
74 | used to buffer writes until it is mostly full, at which point | |
75 | writes transparently revert to writethrough mode. Intended only | |
76 | for benchmarking/testing. | |
77 | ||
78 | What: /sys/block/<disk>/bcache/writeback_delay | |
79 | Date: November 2010 | |
80 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
81 | Description: | |
82 | For backing devices: In writeback mode, when dirty data is | |
83 | written to the cache and the cache held no dirty data for that | |
84 | backing device, writeback from cache to backing device starts | |
85 | after this delay, expressed as an integer number of seconds. | |
86 | ||
87 | What: /sys/block/<disk>/bcache/writeback_percent | |
88 | Date: November 2010 | |
89 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
90 | Description: | |
91 | For backing devices: If nonzero, writeback from cache to | |
92 | backing device only takes place when more than this percentage | |
93 | of the cache is used, allowing more write coalescing to take | |
94 | place and reducing total number of writes sent to the backing | |
95 | device. Integer between 0 and 40. | |
96 | ||
97 | What: /sys/block/<disk>/bcache/synchronous | |
98 | Date: November 2010 | |
99 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
100 | Description: | |
101 | For a cache, a boolean that allows synchronous mode to be | |
102 | switched on and off. In synchronous mode all writes are ordered | |
103 | such that the cache can reliably recover from unclean shutdown; | |
104 | if disabled bcache will not generally wait for writes to | |
105 | complete but if the cache is not shut down cleanly all data | |
106 | will be discarded from the cache. Should not be turned off with | |
107 | writeback caching enabled. | |
108 | ||
109 | What: /sys/block/<disk>/bcache/discard | |
110 | Date: November 2010 | |
111 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
112 | Description: | |
113 | For a cache, a boolean allowing discard/TRIM to be turned off | |
114 | or back on if the device supports it. | |
115 | ||
116 | What: /sys/block/<disk>/bcache/bucket_size | |
117 | Date: November 2010 | |
118 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
119 | Description: | |
120 | For a cache, bucket size in human readable units, as set at | |
121 | cache creation time; should match the erase block size of the | |
122 | SSD for optimal performance. | |
123 | ||
124 | What: /sys/block/<disk>/bcache/nbuckets | |
125 | Date: November 2010 | |
126 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
127 | Description: | |
128 | For a cache, the number of usable buckets. | |
129 | ||
130 | What: /sys/block/<disk>/bcache/tree_depth | |
131 | Date: November 2010 | |
132 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
133 | Description: | |
134 | For a cache, height of the btree excluding leaf nodes (i.e. a | |
135 | one node tree will have a depth of 0). | |
136 | ||
137 | What: /sys/block/<disk>/bcache/btree_cache_size | |
138 | Date: November 2010 | |
139 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
140 | Description: | |
141 | Number of btree buckets/nodes that are currently cached in | |
142 | memory; cache dynamically grows and shrinks in response to | |
143 | memory pressure from the rest of the system. | |
144 | ||
145 | What: /sys/block/<disk>/bcache/written | |
146 | Date: November 2010 | |
147 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
148 | Description: | |
149 | For a cache, total amount of data in human readable units | |
150 | written to the cache, excluding all metadata. | |
151 | ||
152 | What: /sys/block/<disk>/bcache/btree_written | |
153 | Date: November 2010 | |
154 | Contact: Kent Overstreet <kent.overstreet@gmail.com> | |
155 | Description: | |
156 | For a cache, sum of all btree writes in human readable units. |