1 What: /sys/block/<disk>/alignment_of 1 What: /sys/block/<disk>/alignment_offset
2 Date: April 2009 2 Date: April 2009
3 Contact: Martin K. Petersen <martin.pete 3 Contact: Martin K. Petersen <martin.petersen@oracle.com>
4 Description: 4 Description:
5 Storage devices may report a p 5 Storage devices may report a physical block size that is
6 bigger than the logical block 6 bigger than the logical block size (for instance a drive
7 with 4KB physical sectors expo 7 with 4KB physical sectors exposing 512-byte logical
8 blocks to the operating system 8 blocks to the operating system). This parameter
9 indicates how many bytes the b 9 indicates how many bytes the beginning of the device is
10 offset from the disk's natural 10 offset from the disk's natural alignment.
11 11
12 12
13 What: /sys/block/<disk>/discard_alig 13 What: /sys/block/<disk>/discard_alignment
14 Date: May 2011 14 Date: May 2011
15 Contact: Martin K. Petersen <martin.pete 15 Contact: Martin K. Petersen <martin.petersen@oracle.com>
16 Description: 16 Description:
17 Devices that support discard f 17 Devices that support discard functionality may
18 internally allocate space in u 18 internally allocate space in units that are bigger than
19 the exported logical block siz 19 the exported logical block size. The discard_alignment
20 parameter indicates how many b 20 parameter indicates how many bytes the beginning of the
21 device is offset from the inte 21 device is offset from the internal allocation unit's
22 natural alignment. 22 natural alignment.
23 23
24 What: /sys/block/<disk>/atomic_write <<
25 Date: February 2024 <<
26 Contact: Himanshu Madhani <himanshu.madh <<
27 Description: <<
28 [RO] This parameter specifies <<
29 size reported by the device. T <<
30 for merging of writes, where a <<
31 operation must not exceed this <<
32 This parameter may be greater <<
33 atomic_write_unit_max_bytes as <<
34 atomic_write_unit_max_bytes wi <<
35 power-of-two and atomic_write_ <<
36 limited by some other queue li <<
37 This parameter - along with at <<
38 and atomic_write_unit_max_byte <<
39 max_hw_sectors_kb, but may be <<
40 <<
41 <<
42 What: /sys/block/<disk>/atomic_write <<
43 Date: February 2024 <<
44 Contact: Himanshu Madhani <himanshu.madh <<
45 Description: <<
46 [RO] This parameter specifies <<
47 be written atomically with an <<
48 atomic write operations must b <<
49 atomic_write_unit_min boundary <<
50 atomic_write_unit_min. This va <<
51 <<
52 <<
53 What: /sys/block/<disk>/atomic_write <<
54 Date: February 2024 <<
55 Contact: Himanshu Madhani <himanshu.madh <<
56 Description: <<
57 [RO] This parameter defines th <<
58 written atomically with an ato <<
59 value must be a multiple of at <<
60 be a power-of-two. This value <<
61 atomic_write_max_bytes. <<
62 <<
63 <<
64 What: /sys/block/<disk>/atomic_write <<
65 Date: February 2024 <<
66 Contact: Himanshu Madhani <himanshu.madh <<
67 Description: <<
68 [RO] A device may need to inte <<
69 which straddles a given logica <<
70 parameter specifies the size i <<
71 one is reported by the device. <<
72 power-of-two and at least the <<
73 atomic_write_unit_max_bytes. <<
74 Any attempt to merge atomic wr <<
75 merged I/O which crosses this <<
76 <<
77 24
78 What: /sys/block/<disk>/diskseq 25 What: /sys/block/<disk>/diskseq
79 Date: February 2021 26 Date: February 2021
80 Contact: Matteo Croce <mcroce@microsoft. 27 Contact: Matteo Croce <mcroce@microsoft.com>
81 Description: 28 Description:
82 The /sys/block/<disk>/diskseq 29 The /sys/block/<disk>/diskseq files reports the disk
83 sequence number, which is a mo 30 sequence number, which is a monotonically increasing
84 number assigned to every drive 31 number assigned to every drive.
85 Some devices, like the loop de 32 Some devices, like the loop device, refresh such number
86 every time the backing file is 33 every time the backing file is changed.
87 The value type is 64 bit unsig 34 The value type is 64 bit unsigned.
88 35
89 36
90 What: /sys/block/<disk>/inflight 37 What: /sys/block/<disk>/inflight
91 Date: October 2009 38 Date: October 2009
92 Contact: Jens Axboe <axboe@kernel.dk>, N 39 Contact: Jens Axboe <axboe@kernel.dk>, Nikanth Karthikesan <knikanth@suse.de>
93 Description: 40 Description:
94 Reports the number of I/O requ 41 Reports the number of I/O requests currently in progress
95 (pending / in flight) in a dev 42 (pending / in flight) in a device driver. This can be less
96 than the number of requests qu 43 than the number of requests queued in the block device queue.
97 The report contains 2 fields: 44 The report contains 2 fields: one for read requests
98 and one for write requests. 45 and one for write requests.
99 The value type is unsigned int 46 The value type is unsigned int.
100 Cf. Documentation/block/stat.r 47 Cf. Documentation/block/stat.rst which contains a single value for
101 requests in flight. 48 requests in flight.
102 This is related to /sys/block/ 49 This is related to /sys/block/<disk>/queue/nr_requests
103 and for SCSI device also its q 50 and for SCSI device also its queue_depth.
104 51
105 52
106 What: /sys/block/<disk>/integrity/de 53 What: /sys/block/<disk>/integrity/device_is_integrity_capable
107 Date: July 2014 54 Date: July 2014
108 Contact: Martin K. Petersen <martin.pete 55 Contact: Martin K. Petersen <martin.petersen@oracle.com>
109 Description: 56 Description:
110 Indicates whether a storage de 57 Indicates whether a storage device is capable of storing
111 integrity metadata. Set if the 58 integrity metadata. Set if the device is T10 PI-capable.
112 59
113 60
114 What: /sys/block/<disk>/integrity/fo 61 What: /sys/block/<disk>/integrity/format
115 Date: June 2008 62 Date: June 2008
116 Contact: Martin K. Petersen <martin.pete 63 Contact: Martin K. Petersen <martin.petersen@oracle.com>
117 Description: 64 Description:
118 Metadata format for integrity 65 Metadata format for integrity capable block device.
119 E.g. T10-DIF-TYPE1-CRC. 66 E.g. T10-DIF-TYPE1-CRC.
120 67
121 68
122 What: /sys/block/<disk>/integrity/pr 69 What: /sys/block/<disk>/integrity/protection_interval_bytes
123 Date: July 2015 70 Date: July 2015
124 Contact: Martin K. Petersen <martin.pete 71 Contact: Martin K. Petersen <martin.petersen@oracle.com>
125 Description: 72 Description:
126 Describes the number of data b 73 Describes the number of data bytes which are protected
127 by one integrity tuple. Typica 74 by one integrity tuple. Typically the device's logical
128 block size. 75 block size.
129 76
130 77
131 What: /sys/block/<disk>/integrity/re 78 What: /sys/block/<disk>/integrity/read_verify
132 Date: June 2008 79 Date: June 2008
133 Contact: Martin K. Petersen <martin.pete 80 Contact: Martin K. Petersen <martin.petersen@oracle.com>
134 Description: 81 Description:
135 Indicates whether the block la 82 Indicates whether the block layer should verify the
136 integrity of read requests ser 83 integrity of read requests serviced by devices that
137 support sending integrity meta 84 support sending integrity metadata.
138 85
139 86
140 What: /sys/block/<disk>/integrity/ta 87 What: /sys/block/<disk>/integrity/tag_size
141 Date: June 2008 88 Date: June 2008
142 Contact: Martin K. Petersen <martin.pete 89 Contact: Martin K. Petersen <martin.petersen@oracle.com>
143 Description: 90 Description:
144 Number of bytes of integrity t 91 Number of bytes of integrity tag space available per
145 512 bytes of data. 92 512 bytes of data.
146 93
147 94
148 What: /sys/block/<disk>/integrity/wr 95 What: /sys/block/<disk>/integrity/write_generate
149 Date: June 2008 96 Date: June 2008
150 Contact: Martin K. Petersen <martin.pete 97 Contact: Martin K. Petersen <martin.petersen@oracle.com>
151 Description: 98 Description:
152 Indicates whether the block la 99 Indicates whether the block layer should automatically
153 generate checksums for write r 100 generate checksums for write requests bound for
154 devices that support receiving 101 devices that support receiving integrity metadata.
155 102
156 103
157 What: /sys/block/<disk>/partscan 104 What: /sys/block/<disk>/partscan
158 Date: May 2024 105 Date: May 2024
159 Contact: Christoph Hellwig <hch@lst.de> 106 Contact: Christoph Hellwig <hch@lst.de>
160 Description: 107 Description:
161 The /sys/block/<disk>/partscan 108 The /sys/block/<disk>/partscan files reports if partition
162 scanning is enabled for the di 109 scanning is enabled for the disk. It returns "1" if partition
163 scanning is enabled, or "0" if 110 scanning is enabled, or "0" if not. The value type is a 32-bit
164 unsigned integer, but only "0" 111 unsigned integer, but only "0" and "1" are valid values.
165 112
166 113
167 What: /sys/block/<disk>/<partition>/ 114 What: /sys/block/<disk>/<partition>/alignment_offset
168 Date: April 2009 115 Date: April 2009
169 Contact: Martin K. Petersen <martin.pete 116 Contact: Martin K. Petersen <martin.petersen@oracle.com>
170 Description: 117 Description:
171 Storage devices may report a p 118 Storage devices may report a physical block size that is
172 bigger than the logical block 119 bigger than the logical block size (for instance a drive
173 with 4KB physical sectors expo 120 with 4KB physical sectors exposing 512-byte logical
174 blocks to the operating system 121 blocks to the operating system). This parameter
175 indicates how many bytes the b 122 indicates how many bytes the beginning of the partition
176 is offset from the disk's natu 123 is offset from the disk's natural alignment.
177 124
178 125
179 What: /sys/block/<disk>/<partition>/ 126 What: /sys/block/<disk>/<partition>/discard_alignment
180 Date: May 2011 127 Date: May 2011
181 Contact: Martin K. Petersen <martin.pete 128 Contact: Martin K. Petersen <martin.petersen@oracle.com>
182 Description: 129 Description:
183 Devices that support discard f 130 Devices that support discard functionality may
184 internally allocate space in u 131 internally allocate space in units that are bigger than
185 the exported logical block siz 132 the exported logical block size. The discard_alignment
186 parameter indicates how many b 133 parameter indicates how many bytes the beginning of the
187 partition is offset from the i 134 partition is offset from the internal allocation unit's
188 natural alignment. 135 natural alignment.
189 136
190 137
191 What: /sys/block/<disk>/<partition>/ 138 What: /sys/block/<disk>/<partition>/stat
192 Date: February 2008 139 Date: February 2008
193 Contact: Jerome Marchand <jmarchan@redha 140 Contact: Jerome Marchand <jmarchan@redhat.com>
194 Description: 141 Description:
195 The /sys/block/<disk>/<partiti 142 The /sys/block/<disk>/<partition>/stat files display the
196 I/O statistics of partition <p 143 I/O statistics of partition <partition>. The format is the
197 same as the format of /sys/blo 144 same as the format of /sys/block/<disk>/stat.
198 145
199 146
200 What: /sys/block/<disk>/queue/add_ra 147 What: /sys/block/<disk>/queue/add_random
201 Date: June 2010 148 Date: June 2010
202 Contact: linux-block@vger.kernel.org 149 Contact: linux-block@vger.kernel.org
203 Description: 150 Description:
204 [RW] This file allows to turn 151 [RW] This file allows to turn off the disk entropy contribution.
205 Default value of this file is 152 Default value of this file is '1'(on).
206 153
207 154
208 What: /sys/block/<disk>/queue/chunk_ 155 What: /sys/block/<disk>/queue/chunk_sectors
209 Date: September 2016 156 Date: September 2016
210 Contact: Hannes Reinecke <hare@suse.com> 157 Contact: Hannes Reinecke <hare@suse.com>
211 Description: 158 Description:
212 [RO] chunk_sectors has differe 159 [RO] chunk_sectors has different meaning depending on the type
213 of the disk. For a RAID device 160 of the disk. For a RAID device (dm-raid), chunk_sectors
214 indicates the size in 512B sec 161 indicates the size in 512B sectors of the RAID volume stripe
215 segment. For a zoned block dev 162 segment. For a zoned block device, either host-aware or
216 host-managed, chunk_sectors in 163 host-managed, chunk_sectors indicates the size in 512B sectors
217 of the zones of the device, wi 164 of the zones of the device, with the eventual exception of the
218 last zone of the device which 165 last zone of the device which may be smaller.
219 166
220 167
221 What: /sys/block/<disk>/queue/crypto 168 What: /sys/block/<disk>/queue/crypto/
222 Date: February 2022 169 Date: February 2022
223 Contact: linux-block@vger.kernel.org 170 Contact: linux-block@vger.kernel.org
224 Description: 171 Description:
225 The presence of this subdirect 172 The presence of this subdirectory of /sys/block/<disk>/queue/
226 indicates that the device supp 173 indicates that the device supports inline encryption. This
227 subdirectory contains files wh 174 subdirectory contains files which describe the inline encryption
228 capabilities of the device. F 175 capabilities of the device. For more information about inline
229 encryption, refer to Documenta 176 encryption, refer to Documentation/block/inline-encryption.rst.
230 177
231 178
232 What: /sys/block/<disk>/queue/crypto 179 What: /sys/block/<disk>/queue/crypto/max_dun_bits
233 Date: February 2022 180 Date: February 2022
234 Contact: linux-block@vger.kernel.org 181 Contact: linux-block@vger.kernel.org
235 Description: 182 Description:
236 [RO] This file shows the maxim 183 [RO] This file shows the maximum length, in bits, of data unit
237 numbers accepted by the device 184 numbers accepted by the device in inline encryption requests.
238 185
239 186
240 What: /sys/block/<disk>/queue/crypto 187 What: /sys/block/<disk>/queue/crypto/modes/<mode>
241 Date: February 2022 188 Date: February 2022
242 Contact: linux-block@vger.kernel.org 189 Contact: linux-block@vger.kernel.org
243 Description: 190 Description:
244 [RO] For each crypto mode (i.e 191 [RO] For each crypto mode (i.e., encryption/decryption
245 algorithm) the device supports 192 algorithm) the device supports with inline encryption, a file
246 will exist at this location. 193 will exist at this location. It will contain a hexadecimal
247 number that is a bitmask of th 194 number that is a bitmask of the supported data unit sizes, in
248 bytes, for that crypto mode. 195 bytes, for that crypto mode.
249 196
250 Currently, the crypto modes th 197 Currently, the crypto modes that may be supported are:
251 198
252 * AES-256-XTS 199 * AES-256-XTS
253 * AES-128-CBC-ESSIV 200 * AES-128-CBC-ESSIV
254 * Adiantum 201 * Adiantum
255 202
256 For example, if a device suppo 203 For example, if a device supports AES-256-XTS inline encryption
257 with data unit sizes of 512 an 204 with data unit sizes of 512 and 4096 bytes, the file
258 /sys/block/<disk>/queue/crypto 205 /sys/block/<disk>/queue/crypto/modes/AES-256-XTS will exist and
259 will contain "0x1200". 206 will contain "0x1200".
260 207
261 208
262 What: /sys/block/<disk>/queue/crypto 209 What: /sys/block/<disk>/queue/crypto/num_keyslots
263 Date: February 2022 210 Date: February 2022
264 Contact: linux-block@vger.kernel.org 211 Contact: linux-block@vger.kernel.org
265 Description: 212 Description:
266 [RO] This file shows the numbe 213 [RO] This file shows the number of keyslots the device has for
267 use with inline encryption. 214 use with inline encryption.
268 215
269 216
270 What: /sys/block/<disk>/queue/dax 217 What: /sys/block/<disk>/queue/dax
271 Date: June 2016 218 Date: June 2016
272 Contact: linux-block@vger.kernel.org 219 Contact: linux-block@vger.kernel.org
273 Description: 220 Description:
274 [RO] This file indicates wheth 221 [RO] This file indicates whether the device supports Direct
275 Access (DAX), used by CPU-addr 222 Access (DAX), used by CPU-addressable storage to bypass the
276 pagecache. It shows '1' if tr 223 pagecache. It shows '1' if true, '0' if not.
277 224
278 225
279 What: /sys/block/<disk>/queue/discar 226 What: /sys/block/<disk>/queue/discard_granularity
280 Date: May 2011 227 Date: May 2011
281 Contact: Martin K. Petersen <martin.pete 228 Contact: Martin K. Petersen <martin.petersen@oracle.com>
282 Description: 229 Description:
283 [RO] Devices that support disc 230 [RO] Devices that support discard functionality may internally
284 allocate space using units tha 231 allocate space using units that are bigger than the logical
285 block size. The discard_granul 232 block size. The discard_granularity parameter indicates the size
286 of the internal allocation uni 233 of the internal allocation unit in bytes if reported by the
287 device. Otherwise the discard_ 234 device. Otherwise the discard_granularity will be set to match
288 the device's physical block si 235 the device's physical block size. A discard_granularity of 0
289 means that the device does not 236 means that the device does not support discard functionality.
290 237
291 238
292 What: /sys/block/<disk>/queue/discar 239 What: /sys/block/<disk>/queue/discard_max_bytes
293 Date: May 2011 240 Date: May 2011
294 Contact: Martin K. Petersen <martin.pete 241 Contact: Martin K. Petersen <martin.petersen@oracle.com>
295 Description: 242 Description:
296 [RW] While discard_max_hw_byte 243 [RW] While discard_max_hw_bytes is the hardware limit for the
297 device, this setting is the so 244 device, this setting is the software limit. Some devices exhibit
298 large latencies when large dis 245 large latencies when large discards are issued, setting this
299 value lower will make Linux is 246 value lower will make Linux issue smaller discards and
300 potentially help reduce latenc 247 potentially help reduce latencies induced by large discard
301 operations. 248 operations.
302 249
303 250
304 What: /sys/block/<disk>/queue/discar 251 What: /sys/block/<disk>/queue/discard_max_hw_bytes
305 Date: July 2015 252 Date: July 2015
306 Contact: linux-block@vger.kernel.org 253 Contact: linux-block@vger.kernel.org
307 Description: 254 Description:
308 [RO] Devices that support disc 255 [RO] Devices that support discard functionality may have
309 internal limits on the number 256 internal limits on the number of bytes that can be trimmed or
310 unmapped in a single operation 257 unmapped in a single operation. The `discard_max_hw_bytes`
311 parameter is set by the device 258 parameter is set by the device driver to the maximum number of
312 bytes that can be discarded in 259 bytes that can be discarded in a single operation. Discard
313 requests issued to the device 260 requests issued to the device must not exceed this limit. A
314 `discard_max_hw_bytes` value o 261 `discard_max_hw_bytes` value of 0 means that the device does not
315 support discard functionality. 262 support discard functionality.
316 263
317 264
318 What: /sys/block/<disk>/queue/discar 265 What: /sys/block/<disk>/queue/discard_zeroes_data
319 Date: May 2011 266 Date: May 2011
320 Contact: Martin K. Petersen <martin.pete 267 Contact: Martin K. Petersen <martin.petersen@oracle.com>
321 Description: 268 Description:
322 [RO] Will always return 0. Do 269 [RO] Will always return 0. Don't rely on any specific behavior
323 for discards, and don't read t 270 for discards, and don't read this file.
324 271
325 272
326 What: /sys/block/<disk>/queue/dma_al 273 What: /sys/block/<disk>/queue/dma_alignment
327 Date: May 2022 274 Date: May 2022
328 Contact: linux-block@vger.kernel.org 275 Contact: linux-block@vger.kernel.org
329 Description: 276 Description:
330 Reports the alignment that use 277 Reports the alignment that user space addresses must have to be
331 used for raw block device acce 278 used for raw block device access with O_DIRECT and other driver
332 specific passthrough mechanism 279 specific passthrough mechanisms.
333 280
334 281
335 What: /sys/block/<disk>/queue/fua 282 What: /sys/block/<disk>/queue/fua
336 Date: May 2018 283 Date: May 2018
337 Contact: linux-block@vger.kernel.org 284 Contact: linux-block@vger.kernel.org
338 Description: 285 Description:
339 [RO] Whether or not the block 286 [RO] Whether or not the block driver supports the FUA flag for
340 write requests. FUA stands fo 287 write requests. FUA stands for Force Unit Access. If the FUA
341 flag is set that means that wr 288 flag is set that means that write requests must bypass the
342 volatile cache of the storage 289 volatile cache of the storage device.
343 290
344 291
345 What: /sys/block/<disk>/queue/hw_sec 292 What: /sys/block/<disk>/queue/hw_sector_size
346 Date: January 2008 293 Date: January 2008
347 Contact: linux-block@vger.kernel.org 294 Contact: linux-block@vger.kernel.org
348 Description: 295 Description:
349 [RO] This is the hardware sect 296 [RO] This is the hardware sector size of the device, in bytes.
350 297
351 298
352 What: /sys/block/<disk>/queue/indepe 299 What: /sys/block/<disk>/queue/independent_access_ranges/
353 Date: October 2021 300 Date: October 2021
354 Contact: linux-block@vger.kernel.org 301 Contact: linux-block@vger.kernel.org
355 Description: 302 Description:
356 [RO] The presence of this sub- 303 [RO] The presence of this sub-directory of the
357 /sys/block/xxx/queue/ director 304 /sys/block/xxx/queue/ directory indicates that the device is
358 capable of executing requests 305 capable of executing requests targeting different sector ranges
359 in parallel. For instance, sin 306 in parallel. For instance, single LUN multi-actuator hard-disks
360 will have an independent_acces 307 will have an independent_access_ranges directory if the device
361 correctly advertises the secto 308 correctly advertises the sector ranges of its actuators.
362 309
363 The independent_access_ranges 310 The independent_access_ranges directory contains one directory
364 per access range, with each ra 311 per access range, with each range described using the sector
365 (RO) attribute file to indicat 312 (RO) attribute file to indicate the first sector of the range
366 and the nr_sectors (RO) attrib 313 and the nr_sectors (RO) attribute file to indicate the total
367 number of sectors in the range 314 number of sectors in the range starting from the first sector of
368 the range. For example, a dua 315 the range. For example, a dual-actuator hard-disk will have the
369 following independent_access_r 316 following independent_access_ranges entries.::
370 317
371 $ tree /sys/block/<dis 318 $ tree /sys/block/<disk>/queue/independent_access_ranges/
372 /sys/block/<disk>/queu 319 /sys/block/<disk>/queue/independent_access_ranges/
373 |-- 0 320 |-- 0
374 | |-- nr_sectors 321 | |-- nr_sectors
375 | `-- sector 322 | `-- sector
376 `-- 1 323 `-- 1
377 |-- nr_sectors 324 |-- nr_sectors
378 `-- sector 325 `-- sector
379 326
380 The sector and nr_sectors attr 327 The sector and nr_sectors attributes use 512B sector unit,
381 regardless of the actual block 328 regardless of the actual block size of the device. Independent
382 access ranges do not overlap a 329 access ranges do not overlap and include all sectors within the
383 device capacity. The access ra 330 device capacity. The access ranges are numbered in increasing
384 order of the range start secto 331 order of the range start sector, that is, the sector attribute
385 of range 0 always has the valu 332 of range 0 always has the value 0.
386 333
387 334
388 What: /sys/block/<disk>/queue/io_pol 335 What: /sys/block/<disk>/queue/io_poll
389 Date: November 2015 336 Date: November 2015
390 Contact: linux-block@vger.kernel.org 337 Contact: linux-block@vger.kernel.org
391 Description: 338 Description:
392 [RW] When read, this file show 339 [RW] When read, this file shows whether polling is enabled (1)
393 or disabled (0). Writing '0' 340 or disabled (0). Writing '0' to this file will disable polling
394 for this device. Writing any 341 for this device. Writing any non-zero value will enable this
395 feature. 342 feature.
396 343
397 344
398 What: /sys/block/<disk>/queue/io_pol 345 What: /sys/block/<disk>/queue/io_poll_delay
399 Date: November 2016 346 Date: November 2016
400 Contact: linux-block@vger.kernel.org 347 Contact: linux-block@vger.kernel.org
401 Description: 348 Description:
402 [RW] This was used to control 349 [RW] This was used to control what kind of polling will be
403 performed. It is now fixed to 350 performed. It is now fixed to -1, which is classic polling.
404 In this mode, the CPU will rep 351 In this mode, the CPU will repeatedly ask for completions
405 without giving up any time. 352 without giving up any time.
406 <deprecated> 353 <deprecated>
407 354
408 355
409 What: /sys/block/<disk>/queue/io_tim 356 What: /sys/block/<disk>/queue/io_timeout
410 Date: November 2018 357 Date: November 2018
411 Contact: Weiping Zhang <zhangweiping@did 358 Contact: Weiping Zhang <zhangweiping@didiglobal.com>
412 Description: 359 Description:
413 [RW] io_timeout is the request 360 [RW] io_timeout is the request timeout in milliseconds. If a
414 request does not complete in t 361 request does not complete in this time then the block driver
415 timeout handler is invoked. Th 362 timeout handler is invoked. That timeout handler can decide to
416 retry the request, to fail it 363 retry the request, to fail it or to start a device recovery
417 strategy. 364 strategy.
418 365
419 366
420 What: /sys/block/<disk>/queue/iostat 367 What: /sys/block/<disk>/queue/iostats
421 Date: January 2009 368 Date: January 2009
422 Contact: linux-block@vger.kernel.org 369 Contact: linux-block@vger.kernel.org
423 Description: 370 Description:
424 [RW] This file is used to cont 371 [RW] This file is used to control (on/off) the iostats
425 accounting of the disk. 372 accounting of the disk.
426 373
427 374
428 What: /sys/block/<disk>/queue/logica 375 What: /sys/block/<disk>/queue/logical_block_size
429 Date: May 2009 376 Date: May 2009
430 Contact: Martin K. Petersen <martin.pete 377 Contact: Martin K. Petersen <martin.petersen@oracle.com>
431 Description: 378 Description:
432 [RO] This is the smallest unit 379 [RO] This is the smallest unit the storage device can address.
433 It is typically 512 bytes. 380 It is typically 512 bytes.
434 381
435 382
436 What: /sys/block/<disk>/queue/max_ac 383 What: /sys/block/<disk>/queue/max_active_zones
437 Date: July 2020 384 Date: July 2020
438 Contact: Niklas Cassel <niklas.cassel@wd 385 Contact: Niklas Cassel <niklas.cassel@wdc.com>
439 Description: 386 Description:
440 [RO] For zoned block devices ( 387 [RO] For zoned block devices (zoned attribute indicating
441 "host-managed" or "host-aware" 388 "host-managed" or "host-aware"), the sum of zones belonging to
442 any of the zone states: EXPLIC 389 any of the zone states: EXPLICIT OPEN, IMPLICIT OPEN or CLOSED,
443 is limited by this value. If t 390 is limited by this value. If this value is 0, there is no limit.
444 391
445 If the host attempts to exceed 392 If the host attempts to exceed this limit, the driver should
446 report this error with BLK_STS 393 report this error with BLK_STS_ZONE_ACTIVE_RESOURCE, which user
447 space may see as the EOVERFLOW 394 space may see as the EOVERFLOW errno.
448 395
449 396
450 What: /sys/block/<disk>/queue/max_di 397 What: /sys/block/<disk>/queue/max_discard_segments
451 Date: February 2017 398 Date: February 2017
452 Contact: linux-block@vger.kernel.org 399 Contact: linux-block@vger.kernel.org
453 Description: 400 Description:
454 [RO] The maximum number of DMA 401 [RO] The maximum number of DMA scatter/gather entries in a
455 discard request. 402 discard request.
456 403
457 404
458 What: /sys/block/<disk>/queue/max_hw 405 What: /sys/block/<disk>/queue/max_hw_sectors_kb
459 Date: September 2004 406 Date: September 2004
460 Contact: linux-block@vger.kernel.org 407 Contact: linux-block@vger.kernel.org
461 Description: 408 Description:
462 [RO] This is the maximum numbe 409 [RO] This is the maximum number of kilobytes supported in a
463 single data transfer. 410 single data transfer.
464 411
465 412
466 What: /sys/block/<disk>/queue/max_in 413 What: /sys/block/<disk>/queue/max_integrity_segments
467 Date: September 2010 414 Date: September 2010
468 Contact: linux-block@vger.kernel.org 415 Contact: linux-block@vger.kernel.org
469 Description: 416 Description:
470 [RO] Maximum number of element 417 [RO] Maximum number of elements in a DMA scatter/gather list
471 with integrity data that will 418 with integrity data that will be submitted by the block layer
472 core to the associated block d 419 core to the associated block driver.
473 420
474 421
475 What: /sys/block/<disk>/queue/max_op 422 What: /sys/block/<disk>/queue/max_open_zones
476 Date: July 2020 423 Date: July 2020
477 Contact: Niklas Cassel <niklas.cassel@wd 424 Contact: Niklas Cassel <niklas.cassel@wdc.com>
478 Description: 425 Description:
479 [RO] For zoned block devices ( 426 [RO] For zoned block devices (zoned attribute indicating
480 "host-managed" or "host-aware" 427 "host-managed" or "host-aware"), the sum of zones belonging to
481 any of the zone states: EXPLIC 428 any of the zone states: EXPLICIT OPEN or IMPLICIT OPEN, is
482 limited by this value. If this 429 limited by this value. If this value is 0, there is no limit.
483 430
484 431
485 What: /sys/block/<disk>/queue/max_se 432 What: /sys/block/<disk>/queue/max_sectors_kb
486 Date: September 2004 433 Date: September 2004
487 Contact: linux-block@vger.kernel.org 434 Contact: linux-block@vger.kernel.org
488 Description: 435 Description:
489 [RW] This is the maximum numbe 436 [RW] This is the maximum number of kilobytes that the block
490 layer will allow for a filesys 437 layer will allow for a filesystem request. Must be smaller than
491 or equal to the maximum size a 438 or equal to the maximum size allowed by the hardware. Write 0
492 to use default kernel settings 439 to use default kernel settings.
493 440
494 441
495 What: /sys/block/<disk>/queue/max_se 442 What: /sys/block/<disk>/queue/max_segment_size
496 Date: March 2010 443 Date: March 2010
497 Contact: linux-block@vger.kernel.org 444 Contact: linux-block@vger.kernel.org
498 Description: 445 Description:
499 [RO] Maximum size in bytes of 446 [RO] Maximum size in bytes of a single element in a DMA
500 scatter/gather list. 447 scatter/gather list.
501 448
502 449
503 What: /sys/block/<disk>/queue/max_se 450 What: /sys/block/<disk>/queue/max_segments
504 Date: March 2010 451 Date: March 2010
505 Contact: linux-block@vger.kernel.org 452 Contact: linux-block@vger.kernel.org
506 Description: 453 Description:
507 [RO] Maximum number of element 454 [RO] Maximum number of elements in a DMA scatter/gather list
508 that is submitted to the assoc 455 that is submitted to the associated block driver.
509 456
510 457
511 What: /sys/block/<disk>/queue/minimu 458 What: /sys/block/<disk>/queue/minimum_io_size
512 Date: April 2009 459 Date: April 2009
513 Contact: Martin K. Petersen <martin.pete 460 Contact: Martin K. Petersen <martin.petersen@oracle.com>
514 Description: 461 Description:
515 [RO] Storage devices may repor 462 [RO] Storage devices may report a granularity or preferred
516 minimum I/O size which is the 463 minimum I/O size which is the smallest request the device can
517 perform without incurring a pe 464 perform without incurring a performance penalty. For disk
518 drives this is often the physi 465 drives this is often the physical block size. For RAID arrays
519 it is often the stripe chunk s 466 it is often the stripe chunk size. A properly aligned multiple
520 of minimum_io_size is the pref 467 of minimum_io_size is the preferred request size for workloads
521 where a high number of I/O ope 468 where a high number of I/O operations is desired.
522 469
523 470
524 What: /sys/block/<disk>/queue/nomerg 471 What: /sys/block/<disk>/queue/nomerges
525 Date: January 2010 472 Date: January 2010
526 Contact: linux-block@vger.kernel.org 473 Contact: linux-block@vger.kernel.org
527 Description: 474 Description:
528 [RW] Standard I/O elevator ope 475 [RW] Standard I/O elevator operations include attempts to merge
529 contiguous I/Os. For known ran 476 contiguous I/Os. For known random I/O loads these attempts will
530 always fail and result in extr 477 always fail and result in extra cycles being spent in the
531 kernel. This allows one to tur 478 kernel. This allows one to turn off this behavior on one of two
532 ways: When set to 1, complex m 479 ways: When set to 1, complex merge checks are disabled, but the
533 simple one-shot merges with th 480 simple one-shot merges with the previous I/O request are
534 enabled. When set to 2, all me 481 enabled. When set to 2, all merge tries are disabled. The
535 default value is 0 - which ena 482 default value is 0 - which enables all types of merge tries.
536 483
537 484
538 What: /sys/block/<disk>/queue/nr_req 485 What: /sys/block/<disk>/queue/nr_requests
539 Date: July 2003 486 Date: July 2003
540 Contact: linux-block@vger.kernel.org 487 Contact: linux-block@vger.kernel.org
541 Description: 488 Description:
542 [RW] This controls how many re 489 [RW] This controls how many requests may be allocated in the
543 block layer for read or write 490 block layer for read or write requests. Note that the total
544 allocated number may be twice 491 allocated number may be twice this amount, since it applies only
545 to reads or writes (not the ac 492 to reads or writes (not the accumulated sum).
546 493
547 To avoid priority inversion th 494 To avoid priority inversion through request starvation, a
548 request queue maintains a sepa 495 request queue maintains a separate request pool per each cgroup
549 when CONFIG_BLK_CGROUP is enab 496 when CONFIG_BLK_CGROUP is enabled, and this parameter applies to
550 each such per-block-cgroup req 497 each such per-block-cgroup request pool. IOW, if there are N
551 block cgroups, each request qu 498 block cgroups, each request queue may have up to N request
552 pools, each independently regu 499 pools, each independently regulated by nr_requests.
553 500
554 501
555 What: /sys/block/<disk>/queue/nr_zon 502 What: /sys/block/<disk>/queue/nr_zones
556 Date: November 2018 503 Date: November 2018
557 Contact: Damien Le Moal <damien.lemoal@w 504 Contact: Damien Le Moal <damien.lemoal@wdc.com>
558 Description: 505 Description:
559 [RO] nr_zones indicates the to 506 [RO] nr_zones indicates the total number of zones of a zoned
560 block device ("host-aware" or 507 block device ("host-aware" or "host-managed" zone model). For
561 regular block devices, the val 508 regular block devices, the value is always 0.
562 509
563 510
564 What: /sys/block/<disk>/queue/optima 511 What: /sys/block/<disk>/queue/optimal_io_size
565 Date: April 2009 512 Date: April 2009
566 Contact: Martin K. Petersen <martin.pete 513 Contact: Martin K. Petersen <martin.petersen@oracle.com>
567 Description: 514 Description:
568 [RO] Storage devices may repor 515 [RO] Storage devices may report an optimal I/O size, which is
569 the device's preferred unit fo 516 the device's preferred unit for sustained I/O. This is rarely
570 reported for disk drives. For 517 reported for disk drives. For RAID arrays it is usually the
571 stripe width or the internal t 518 stripe width or the internal track size. A properly aligned
572 multiple of optimal_io_size is 519 multiple of optimal_io_size is the preferred request size for
573 workloads where sustained thro 520 workloads where sustained throughput is desired. If no optimal
574 I/O size is reported this file 521 I/O size is reported this file contains 0.
575 522
576 523
577 What: /sys/block/<disk>/queue/physic 524 What: /sys/block/<disk>/queue/physical_block_size
578 Date: May 2009 525 Date: May 2009
579 Contact: Martin K. Petersen <martin.pete 526 Contact: Martin K. Petersen <martin.petersen@oracle.com>
580 Description: 527 Description:
581 [RO] This is the smallest unit 528 [RO] This is the smallest unit a physical storage device can
582 write atomically. It is usual 529 write atomically. It is usually the same as the logical block
583 size but may be bigger. One e 530 size but may be bigger. One example is SATA drives with 4KB
584 sectors that expose a 512-byte 531 sectors that expose a 512-byte logical block size to the
585 operating system. For stacked 532 operating system. For stacked block devices the
586 physical_block_size variable c 533 physical_block_size variable contains the maximum
587 physical_block_size of the com 534 physical_block_size of the component devices.
588 535
589 536
590 What: /sys/block/<disk>/queue/read_a 537 What: /sys/block/<disk>/queue/read_ahead_kb
591 Date: May 2004 538 Date: May 2004
592 Contact: linux-block@vger.kernel.org 539 Contact: linux-block@vger.kernel.org
593 Description: 540 Description:
594 [RW] Maximum number of kilobyt 541 [RW] Maximum number of kilobytes to read-ahead for filesystems
595 on this block device. 542 on this block device.
596 543
597 544
598 What: /sys/block/<disk>/queue/rotati 545 What: /sys/block/<disk>/queue/rotational
599 Date: January 2009 546 Date: January 2009
600 Contact: linux-block@vger.kernel.org 547 Contact: linux-block@vger.kernel.org
601 Description: 548 Description:
602 [RW] This file is used to stat 549 [RW] This file is used to stat if the device is of rotational
603 type or non-rotational type. 550 type or non-rotational type.
604 551
605 552
606 What: /sys/block/<disk>/queue/rq_aff 553 What: /sys/block/<disk>/queue/rq_affinity
607 Date: September 2008 554 Date: September 2008
608 Contact: linux-block@vger.kernel.org 555 Contact: linux-block@vger.kernel.org
609 Description: 556 Description:
610 [RW] If this option is '1', th 557 [RW] If this option is '1', the block layer will migrate request
611 completions to the cpu "group" 558 completions to the cpu "group" that originally submitted the
612 request. For some workloads th 559 request. For some workloads this provides a significant
613 reduction in CPU cycles due to 560 reduction in CPU cycles due to caching effects.
614 561
615 For storage configurations tha 562 For storage configurations that need to maximize distribution of
616 completion processing setting 563 completion processing setting this option to '2' forces the
617 completion to run on the reque 564 completion to run on the requesting cpu (bypassing the "group"
618 aggregation logic). 565 aggregation logic).
619 566
620 567
621 What: /sys/block/<disk>/queue/schedu 568 What: /sys/block/<disk>/queue/scheduler
622 Date: October 2004 569 Date: October 2004
623 Contact: linux-block@vger.kernel.org 570 Contact: linux-block@vger.kernel.org
624 Description: 571 Description:
625 [RW] When read, this file will 572 [RW] When read, this file will display the current and available
626 IO schedulers for this block d 573 IO schedulers for this block device. The currently active IO
627 scheduler will be enclosed in 574 scheduler will be enclosed in [] brackets. Writing an IO
628 scheduler name to this file wi 575 scheduler name to this file will switch control of this block
629 device to that new IO schedule 576 device to that new IO scheduler. Note that writing an IO
630 scheduler name to this file wi 577 scheduler name to this file will attempt to load that IO
631 scheduler module, if it isn't 578 scheduler module, if it isn't already present in the system.
632 579
633 580
634 What: /sys/block/<disk>/queue/stable 581 What: /sys/block/<disk>/queue/stable_writes
635 Date: September 2020 582 Date: September 2020
636 Contact: linux-block@vger.kernel.org 583 Contact: linux-block@vger.kernel.org
637 Description: 584 Description:
638 [RW] This file will contain '1 585 [RW] This file will contain '1' if memory must not be modified
639 while it is being used in a wr 586 while it is being used in a write request to this device. When
640 this is the case and the kerne 587 this is the case and the kernel is performing writeback of a
641 page, the kernel will wait for 588 page, the kernel will wait for writeback to complete before
642 allowing the page to be modifi 589 allowing the page to be modified again, rather than allowing
643 immediate modification as is n 590 immediate modification as is normally the case. This
644 restriction arises when the de 591 restriction arises when the device accesses the memory multiple
645 times where the same data must 592 times where the same data must be seen every time -- for
646 example, once to calculate a c 593 example, once to calculate a checksum and once to actually write
647 the data. If no such restrict 594 the data. If no such restriction exists, this file will contain
648 '0'. This file is writable fo 595 '0'. This file is writable for testing purposes.
>> 596
>> 597
>> 598 What: /sys/block/<disk>/queue/throttle_sample_time
>> 599 Date: March 2017
>> 600 Contact: linux-block@vger.kernel.org
>> 601 Description:
>> 602 [RW] This is the time window that blk-throttle samples data, in
>> 603 millisecond. blk-throttle makes decision based on the
>> 604 samplings. Lower time means cgroups have more smooth throughput,
>> 605 but higher CPU overhead. This exists only when
>> 606 CONFIG_BLK_DEV_THROTTLING_LOW is enabled.
>> 607
649 608
650 What: /sys/block/<disk>/queue/virt_b 609 What: /sys/block/<disk>/queue/virt_boundary_mask
651 Date: April 2021 610 Date: April 2021
652 Contact: linux-block@vger.kernel.org 611 Contact: linux-block@vger.kernel.org
653 Description: 612 Description:
654 [RO] This file shows the I/O s 613 [RO] This file shows the I/O segment memory alignment mask for
655 the block device. I/O request 614 the block device. I/O requests to this device will be split
656 between segments wherever eith 615 between segments wherever either the memory address of the end
657 of the previous segment or the 616 of the previous segment or the memory address of the beginning
658 of the current segment is not 617 of the current segment is not aligned to virt_boundary_mask + 1
659 bytes. 618 bytes.
660 619
661 620
662 What: /sys/block/<disk>/queue/wbt_la 621 What: /sys/block/<disk>/queue/wbt_lat_usec
663 Date: November 2016 622 Date: November 2016
664 Contact: linux-block@vger.kernel.org 623 Contact: linux-block@vger.kernel.org
665 Description: 624 Description:
666 [RW] If the device is register 625 [RW] If the device is registered for writeback throttling, then
667 this file shows the target min 626 this file shows the target minimum read latency. If this latency
668 is exceeded in a given window 627 is exceeded in a given window of time (see wb_window_usec), then
669 the writeback throttling will 628 the writeback throttling will start scaling back writes. Writing
670 a value of '0' to this file di 629 a value of '0' to this file disables the feature. Writing a
671 value of '-1' to this file res 630 value of '-1' to this file resets the value to the default
672 setting. 631 setting.
673 632
674 633
675 What: /sys/block/<disk>/queue/write_ 634 What: /sys/block/<disk>/queue/write_cache
676 Date: April 2016 635 Date: April 2016
677 Contact: linux-block@vger.kernel.org 636 Contact: linux-block@vger.kernel.org
678 Description: 637 Description:
679 [RW] When read, this file will 638 [RW] When read, this file will display whether the device has
680 write back caching enabled or 639 write back caching enabled or not. It will return "write back"
681 for the former case, and "writ 640 for the former case, and "write through" for the latter. Writing
682 to this file can change the ke 641 to this file can change the kernels view of the device, but it
683 doesn't alter the device state 642 doesn't alter the device state. This means that it might not be
684 safe to toggle the setting fro 643 safe to toggle the setting from "write back" to "write through",
685 since that will also eliminate 644 since that will also eliminate cache flushes issued by the
686 kernel. 645 kernel.
687 646
688 647
689 What: /sys/block/<disk>/queue/write_ 648 What: /sys/block/<disk>/queue/write_same_max_bytes
690 Date: January 2012 649 Date: January 2012
691 Contact: Martin K. Petersen <martin.pete 650 Contact: Martin K. Petersen <martin.petersen@oracle.com>
692 Description: 651 Description:
693 [RO] Some devices support a wr 652 [RO] Some devices support a write same operation in which a
694 single data block can be writt 653 single data block can be written to a range of several
695 contiguous blocks on storage. 654 contiguous blocks on storage. This can be used to wipe areas on
696 disk or to initialize drives i 655 disk or to initialize drives in a RAID configuration.
697 write_same_max_bytes indicates 656 write_same_max_bytes indicates how many bytes can be written in
698 a single write same command. I 657 a single write same command. If write_same_max_bytes is 0, write
699 same is not supported by the d 658 same is not supported by the device.
700 659
701 660
702 What: /sys/block/<disk>/queue/write_ 661 What: /sys/block/<disk>/queue/write_zeroes_max_bytes
703 Date: November 2016 662 Date: November 2016
704 Contact: Chaitanya Kulkarni <chaitanya.k 663 Contact: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
705 Description: 664 Description:
706 [RO] Devices that support writ 665 [RO] Devices that support write zeroes operation in which a
707 single request can be issued t 666 single request can be issued to zero out the range of contiguous
708 blocks on storage without havi 667 blocks on storage without having any payload in the request.
709 This can be used to optimize w 668 This can be used to optimize writing zeroes to the devices.
710 write_zeroes_max_bytes indicat 669 write_zeroes_max_bytes indicates how many bytes can be written
711 in a single write zeroes comma 670 in a single write zeroes command. If write_zeroes_max_bytes is
712 0, write zeroes is not support 671 0, write zeroes is not supported by the device.
713 672
714 673
715 What: /sys/block/<disk>/queue/zone_a 674 What: /sys/block/<disk>/queue/zone_append_max_bytes
716 Date: May 2020 675 Date: May 2020
717 Contact: linux-block@vger.kernel.org 676 Contact: linux-block@vger.kernel.org
718 Description: 677 Description:
719 [RO] This is the maximum numbe 678 [RO] This is the maximum number of bytes that can be written to
720 a sequential zone of a zoned b 679 a sequential zone of a zoned block device using a zone append
721 write operation (REQ_OP_ZONE_A 680 write operation (REQ_OP_ZONE_APPEND). This value is always 0 for
722 regular block devices. 681 regular block devices.
723 682
724 683
725 What: /sys/block/<disk>/queue/zone_w 684 What: /sys/block/<disk>/queue/zone_write_granularity
726 Date: January 2021 685 Date: January 2021
727 Contact: linux-block@vger.kernel.org 686 Contact: linux-block@vger.kernel.org
728 Description: 687 Description:
729 [RO] This indicates the alignm 688 [RO] This indicates the alignment constraint, in bytes, for
730 write operations in sequential 689 write operations in sequential zones of zoned block devices
731 (devices with a zoned attribut 690 (devices with a zoned attributed that reports "host-managed" or
732 "host-aware"). This value is a 691 "host-aware"). This value is always 0 for regular block devices.
733 692
734 693
735 What: /sys/block/<disk>/queue/zoned 694 What: /sys/block/<disk>/queue/zoned
736 Date: September 2016 695 Date: September 2016
737 Contact: Damien Le Moal <damien.lemoal@w 696 Contact: Damien Le Moal <damien.lemoal@wdc.com>
738 Description: 697 Description:
739 [RO] zoned indicates if the de 698 [RO] zoned indicates if the device is a zoned block device and
740 the zone model of the device i 699 the zone model of the device if it is indeed zoned. The
741 possible values indicated by z 700 possible values indicated by zoned are "none" for regular block
742 devices and "host-aware" or "h 701 devices and "host-aware" or "host-managed" for zoned block
743 devices. The characteristics o 702 devices. The characteristics of host-aware and host-managed
744 zoned block devices are descri 703 zoned block devices are described in the ZBC (Zoned Block
745 Commands) and ZAC (Zoned Devic 704 Commands) and ZAC (Zoned Device ATA Command Set) standards.
746 These standards also define th 705 These standards also define the "drive-managed" zone model.
747 However, since drive-managed z 706 However, since drive-managed zoned block devices do not support
748 zone commands, they will be tr 707 zone commands, they will be treated as regular block devices and
749 zoned will report "none". 708 zoned will report "none".
750 709
751 710
752 What: /sys/block/<disk>/hidden 711 What: /sys/block/<disk>/hidden
753 Date: March 2023 712 Date: March 2023
754 Contact: linux-block@vger.kernel.org 713 Contact: linux-block@vger.kernel.org
755 Description: 714 Description:
756 [RO] the block device is hidde 715 [RO] the block device is hidden. it doesn’t produce events, and
757 can’t be opened from userspa 716 can’t be opened from userspace or using blkdev_get*.
758 Used for the underlying compon 717 Used for the underlying components of multipath devices.
759 718
760 719
761 What: /sys/block/<disk>/stat 720 What: /sys/block/<disk>/stat
762 Date: February 2008 721 Date: February 2008
763 Contact: Jerome Marchand <jmarchan@redha 722 Contact: Jerome Marchand <jmarchan@redhat.com>
764 Description: 723 Description:
765 The /sys/block/<disk>/stat fil 724 The /sys/block/<disk>/stat files displays the I/O
766 statistics of disk <disk>. The 725 statistics of disk <disk>. They contain 11 fields:
767 726
768 == ========================== 727 == ==============================================
769 1 reads completed successful 728 1 reads completed successfully
770 2 reads merged 729 2 reads merged
771 3 sectors read 730 3 sectors read
772 4 time spent reading (ms) 731 4 time spent reading (ms)
773 5 writes completed 732 5 writes completed
774 6 writes merged 733 6 writes merged
775 7 sectors written 734 7 sectors written
776 8 time spent writing (ms) 735 8 time spent writing (ms)
777 9 I/Os currently in progress 736 9 I/Os currently in progress
778 10 time spent doing I/Os (ms) 737 10 time spent doing I/Os (ms)
779 11 weighted time spent doing 738 11 weighted time spent doing I/Os (ms)
780 12 discards completed 739 12 discards completed
781 13 discards merged 740 13 discards merged
782 14 sectors discarded 741 14 sectors discarded
783 15 time spent discarding (ms) 742 15 time spent discarding (ms)
784 16 flush requests completed 743 16 flush requests completed
785 17 time spent flushing (ms) 744 17 time spent flushing (ms)
786 == ========================== 745 == ==============================================
787 746
788 For more details refer Documen 747 For more details refer Documentation/admin-guide/iostats.rst
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