1 What: /sys/block/<disk>/alignment_of
2 Date: April 2009
3 Contact: Martin K. Petersen <martin.pete
4 Description:
5 Storage devices may report a p
6 bigger than the logical block
7 with 4KB physical sectors expo
8 blocks to the operating system
9 indicates how many bytes the b
10 offset from the disk's natural
11
12
13 What: /sys/block/<disk>/discard_alig
14 Date: May 2011
15 Contact: Martin K. Petersen <martin.pete
16 Description:
17 Devices that support discard f
18 internally allocate space in u
19 the exported logical block siz
20 parameter indicates how many b
21 device is offset from the inte
22 natural alignment.
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
78 What: /sys/block/<disk>/diskseq
79 Date: February 2021
80 Contact: Matteo Croce <mcroce@microsoft.
81 Description:
82 The /sys/block/<disk>/diskseq
83 sequence number, which is a mo
84 number assigned to every drive
85 Some devices, like the loop de
86 every time the backing file is
87 The value type is 64 bit unsig
88
89
90 What: /sys/block/<disk>/inflight
91 Date: October 2009
92 Contact: Jens Axboe <axboe@kernel.dk>, N
93 Description:
94 Reports the number of I/O requ
95 (pending / in flight) in a dev
96 than the number of requests qu
97 The report contains 2 fields:
98 and one for write requests.
99 The value type is unsigned int
100 Cf. Documentation/block/stat.r
101 requests in flight.
102 This is related to /sys/block/
103 and for SCSI device also its q
104
105
106 What: /sys/block/<disk>/integrity/de
107 Date: July 2014
108 Contact: Martin K. Petersen <martin.pete
109 Description:
110 Indicates whether a storage de
111 integrity metadata. Set if the
112
113
114 What: /sys/block/<disk>/integrity/fo
115 Date: June 2008
116 Contact: Martin K. Petersen <martin.pete
117 Description:
118 Metadata format for integrity
119 E.g. T10-DIF-TYPE1-CRC.
120
121
122 What: /sys/block/<disk>/integrity/pr
123 Date: July 2015
124 Contact: Martin K. Petersen <martin.pete
125 Description:
126 Describes the number of data b
127 by one integrity tuple. Typica
128 block size.
129
130
131 What: /sys/block/<disk>/integrity/re
132 Date: June 2008
133 Contact: Martin K. Petersen <martin.pete
134 Description:
135 Indicates whether the block la
136 integrity of read requests ser
137 support sending integrity meta
138
139
140 What: /sys/block/<disk>/integrity/ta
141 Date: June 2008
142 Contact: Martin K. Petersen <martin.pete
143 Description:
144 Number of bytes of integrity t
145 512 bytes of data.
146
147
148 What: /sys/block/<disk>/integrity/wr
149 Date: June 2008
150 Contact: Martin K. Petersen <martin.pete
151 Description:
152 Indicates whether the block la
153 generate checksums for write r
154 devices that support receiving
155
156
157 What: /sys/block/<disk>/partscan
158 Date: May 2024
159 Contact: Christoph Hellwig <hch@lst.de>
160 Description:
161 The /sys/block/<disk>/partscan
162 scanning is enabled for the di
163 scanning is enabled, or "0" if
164 unsigned integer, but only "0"
165
166
167 What: /sys/block/<disk>/<partition>/
168 Date: April 2009
169 Contact: Martin K. Petersen <martin.pete
170 Description:
171 Storage devices may report a p
172 bigger than the logical block
173 with 4KB physical sectors expo
174 blocks to the operating system
175 indicates how many bytes the b
176 is offset from the disk's natu
177
178
179 What: /sys/block/<disk>/<partition>/
180 Date: May 2011
181 Contact: Martin K. Petersen <martin.pete
182 Description:
183 Devices that support discard f
184 internally allocate space in u
185 the exported logical block siz
186 parameter indicates how many b
187 partition is offset from the i
188 natural alignment.
189
190
191 What: /sys/block/<disk>/<partition>/
192 Date: February 2008
193 Contact: Jerome Marchand <jmarchan@redha
194 Description:
195 The /sys/block/<disk>/<partiti
196 I/O statistics of partition <p
197 same as the format of /sys/blo
198
199
200 What: /sys/block/<disk>/queue/add_ra
201 Date: June 2010
202 Contact: linux-block@vger.kernel.org
203 Description:
204 [RW] This file allows to turn
205 Default value of this file is
206
207
208 What: /sys/block/<disk>/queue/chunk_
209 Date: September 2016
210 Contact: Hannes Reinecke <hare@suse.com>
211 Description:
212 [RO] chunk_sectors has differe
213 of the disk. For a RAID device
214 indicates the size in 512B sec
215 segment. For a zoned block dev
216 host-managed, chunk_sectors in
217 of the zones of the device, wi
218 last zone of the device which
219
220
221 What: /sys/block/<disk>/queue/crypto
222 Date: February 2022
223 Contact: linux-block@vger.kernel.org
224 Description:
225 The presence of this subdirect
226 indicates that the device supp
227 subdirectory contains files wh
228 capabilities of the device. F
229 encryption, refer to Documenta
230
231
232 What: /sys/block/<disk>/queue/crypto
233 Date: February 2022
234 Contact: linux-block@vger.kernel.org
235 Description:
236 [RO] This file shows the maxim
237 numbers accepted by the device
238
239
240 What: /sys/block/<disk>/queue/crypto
241 Date: February 2022
242 Contact: linux-block@vger.kernel.org
243 Description:
244 [RO] For each crypto mode (i.e
245 algorithm) the device supports
246 will exist at this location.
247 number that is a bitmask of th
248 bytes, for that crypto mode.
249
250 Currently, the crypto modes th
251
252 * AES-256-XTS
253 * AES-128-CBC-ESSIV
254 * Adiantum
255
256 For example, if a device suppo
257 with data unit sizes of 512 an
258 /sys/block/<disk>/queue/crypto
259 will contain "0x1200".
260
261
262 What: /sys/block/<disk>/queue/crypto
263 Date: February 2022
264 Contact: linux-block@vger.kernel.org
265 Description:
266 [RO] This file shows the numbe
267 use with inline encryption.
268
269
270 What: /sys/block/<disk>/queue/dax
271 Date: June 2016
272 Contact: linux-block@vger.kernel.org
273 Description:
274 [RO] This file indicates wheth
275 Access (DAX), used by CPU-addr
276 pagecache. It shows '1' if tr
277
278
279 What: /sys/block/<disk>/queue/discar
280 Date: May 2011
281 Contact: Martin K. Petersen <martin.pete
282 Description:
283 [RO] Devices that support disc
284 allocate space using units tha
285 block size. The discard_granul
286 of the internal allocation uni
287 device. Otherwise the discard_
288 the device's physical block si
289 means that the device does not
290
291
292 What: /sys/block/<disk>/queue/discar
293 Date: May 2011
294 Contact: Martin K. Petersen <martin.pete
295 Description:
296 [RW] While discard_max_hw_byte
297 device, this setting is the so
298 large latencies when large dis
299 value lower will make Linux is
300 potentially help reduce latenc
301 operations.
302
303
304 What: /sys/block/<disk>/queue/discar
305 Date: July 2015
306 Contact: linux-block@vger.kernel.org
307 Description:
308 [RO] Devices that support disc
309 internal limits on the number
310 unmapped in a single operation
311 parameter is set by the device
312 bytes that can be discarded in
313 requests issued to the device
314 `discard_max_hw_bytes` value o
315 support discard functionality.
316
317
318 What: /sys/block/<disk>/queue/discar
319 Date: May 2011
320 Contact: Martin K. Petersen <martin.pete
321 Description:
322 [RO] Will always return 0. Do
323 for discards, and don't read t
324
325
326 What: /sys/block/<disk>/queue/dma_al
327 Date: May 2022
328 Contact: linux-block@vger.kernel.org
329 Description:
330 Reports the alignment that use
331 used for raw block device acce
332 specific passthrough mechanism
333
334
335 What: /sys/block/<disk>/queue/fua
336 Date: May 2018
337 Contact: linux-block@vger.kernel.org
338 Description:
339 [RO] Whether or not the block
340 write requests. FUA stands fo
341 flag is set that means that wr
342 volatile cache of the storage
343
344
345 What: /sys/block/<disk>/queue/hw_sec
346 Date: January 2008
347 Contact: linux-block@vger.kernel.org
348 Description:
349 [RO] This is the hardware sect
350
351
352 What: /sys/block/<disk>/queue/indepe
353 Date: October 2021
354 Contact: linux-block@vger.kernel.org
355 Description:
356 [RO] The presence of this sub-
357 /sys/block/xxx/queue/ director
358 capable of executing requests
359 in parallel. For instance, sin
360 will have an independent_acces
361 correctly advertises the secto
362
363 The independent_access_ranges
364 per access range, with each ra
365 (RO) attribute file to indicat
366 and the nr_sectors (RO) attrib
367 number of sectors in the range
368 the range. For example, a dua
369 following independent_access_r
370
371 $ tree /sys/block/<dis
372 /sys/block/<disk>/queu
373 |-- 0
374 | |-- nr_sectors
375 | `-- sector
376 `-- 1
377 |-- nr_sectors
378 `-- sector
379
380 The sector and nr_sectors attr
381 regardless of the actual block
382 access ranges do not overlap a
383 device capacity. The access ra
384 order of the range start secto
385 of range 0 always has the valu
386
387
388 What: /sys/block/<disk>/queue/io_pol
389 Date: November 2015
390 Contact: linux-block@vger.kernel.org
391 Description:
392 [RW] When read, this file show
393 or disabled (0). Writing '0'
394 for this device. Writing any
395 feature.
396
397
398 What: /sys/block/<disk>/queue/io_pol
399 Date: November 2016
400 Contact: linux-block@vger.kernel.org
401 Description:
402 [RW] This was used to control
403 performed. It is now fixed to
404 In this mode, the CPU will rep
405 without giving up any time.
406 <deprecated>
407
408
409 What: /sys/block/<disk>/queue/io_tim
410 Date: November 2018
411 Contact: Weiping Zhang <zhangweiping@did
412 Description:
413 [RW] io_timeout is the request
414 request does not complete in t
415 timeout handler is invoked. Th
416 retry the request, to fail it
417 strategy.
418
419
420 What: /sys/block/<disk>/queue/iostat
421 Date: January 2009
422 Contact: linux-block@vger.kernel.org
423 Description:
424 [RW] This file is used to cont
425 accounting of the disk.
426
427
428 What: /sys/block/<disk>/queue/logica
429 Date: May 2009
430 Contact: Martin K. Petersen <martin.pete
431 Description:
432 [RO] This is the smallest unit
433 It is typically 512 bytes.
434
435
436 What: /sys/block/<disk>/queue/max_ac
437 Date: July 2020
438 Contact: Niklas Cassel <niklas.cassel@wd
439 Description:
440 [RO] For zoned block devices (
441 "host-managed" or "host-aware"
442 any of the zone states: EXPLIC
443 is limited by this value. If t
444
445 If the host attempts to exceed
446 report this error with BLK_STS
447 space may see as the EOVERFLOW
448
449
450 What: /sys/block/<disk>/queue/max_di
451 Date: February 2017
452 Contact: linux-block@vger.kernel.org
453 Description:
454 [RO] The maximum number of DMA
455 discard request.
456
457
458 What: /sys/block/<disk>/queue/max_hw
459 Date: September 2004
460 Contact: linux-block@vger.kernel.org
461 Description:
462 [RO] This is the maximum numbe
463 single data transfer.
464
465
466 What: /sys/block/<disk>/queue/max_in
467 Date: September 2010
468 Contact: linux-block@vger.kernel.org
469 Description:
470 [RO] Maximum number of element
471 with integrity data that will
472 core to the associated block d
473
474
475 What: /sys/block/<disk>/queue/max_op
476 Date: July 2020
477 Contact: Niklas Cassel <niklas.cassel@wd
478 Description:
479 [RO] For zoned block devices (
480 "host-managed" or "host-aware"
481 any of the zone states: EXPLIC
482 limited by this value. If this
483
484
485 What: /sys/block/<disk>/queue/max_se
486 Date: September 2004
487 Contact: linux-block@vger.kernel.org
488 Description:
489 [RW] This is the maximum numbe
490 layer will allow for a filesys
491 or equal to the maximum size a
492 to use default kernel settings
493
494
495 What: /sys/block/<disk>/queue/max_se
496 Date: March 2010
497 Contact: linux-block@vger.kernel.org
498 Description:
499 [RO] Maximum size in bytes of
500 scatter/gather list.
501
502
503 What: /sys/block/<disk>/queue/max_se
504 Date: March 2010
505 Contact: linux-block@vger.kernel.org
506 Description:
507 [RO] Maximum number of element
508 that is submitted to the assoc
509
510
511 What: /sys/block/<disk>/queue/minimu
512 Date: April 2009
513 Contact: Martin K. Petersen <martin.pete
514 Description:
515 [RO] Storage devices may repor
516 minimum I/O size which is the
517 perform without incurring a pe
518 drives this is often the physi
519 it is often the stripe chunk s
520 of minimum_io_size is the pref
521 where a high number of I/O ope
522
523
524 What: /sys/block/<disk>/queue/nomerg
525 Date: January 2010
526 Contact: linux-block@vger.kernel.org
527 Description:
528 [RW] Standard I/O elevator ope
529 contiguous I/Os. For known ran
530 always fail and result in extr
531 kernel. This allows one to tur
532 ways: When set to 1, complex m
533 simple one-shot merges with th
534 enabled. When set to 2, all me
535 default value is 0 - which ena
536
537
538 What: /sys/block/<disk>/queue/nr_req
539 Date: July 2003
540 Contact: linux-block@vger.kernel.org
541 Description:
542 [RW] This controls how many re
543 block layer for read or write
544 allocated number may be twice
545 to reads or writes (not the ac
546
547 To avoid priority inversion th
548 request queue maintains a sepa
549 when CONFIG_BLK_CGROUP is enab
550 each such per-block-cgroup req
551 block cgroups, each request qu
552 pools, each independently regu
553
554
555 What: /sys/block/<disk>/queue/nr_zon
556 Date: November 2018
557 Contact: Damien Le Moal <damien.lemoal@w
558 Description:
559 [RO] nr_zones indicates the to
560 block device ("host-aware" or
561 regular block devices, the val
562
563
564 What: /sys/block/<disk>/queue/optima
565 Date: April 2009
566 Contact: Martin K. Petersen <martin.pete
567 Description:
568 [RO] Storage devices may repor
569 the device's preferred unit fo
570 reported for disk drives. For
571 stripe width or the internal t
572 multiple of optimal_io_size is
573 workloads where sustained thro
574 I/O size is reported this file
575
576
577 What: /sys/block/<disk>/queue/physic
578 Date: May 2009
579 Contact: Martin K. Petersen <martin.pete
580 Description:
581 [RO] This is the smallest unit
582 write atomically. It is usual
583 size but may be bigger. One e
584 sectors that expose a 512-byte
585 operating system. For stacked
586 physical_block_size variable c
587 physical_block_size of the com
588
589
590 What: /sys/block/<disk>/queue/read_a
591 Date: May 2004
592 Contact: linux-block@vger.kernel.org
593 Description:
594 [RW] Maximum number of kilobyt
595 on this block device.
596
597
598 What: /sys/block/<disk>/queue/rotati
599 Date: January 2009
600 Contact: linux-block@vger.kernel.org
601 Description:
602 [RW] This file is used to stat
603 type or non-rotational type.
604
605
606 What: /sys/block/<disk>/queue/rq_aff
607 Date: September 2008
608 Contact: linux-block@vger.kernel.org
609 Description:
610 [RW] If this option is '1', th
611 completions to the cpu "group"
612 request. For some workloads th
613 reduction in CPU cycles due to
614
615 For storage configurations tha
616 completion processing setting
617 completion to run on the reque
618 aggregation logic).
619
620
621 What: /sys/block/<disk>/queue/schedu
622 Date: October 2004
623 Contact: linux-block@vger.kernel.org
624 Description:
625 [RW] When read, this file will
626 IO schedulers for this block d
627 scheduler will be enclosed in
628 scheduler name to this file wi
629 device to that new IO schedule
630 scheduler name to this file wi
631 scheduler module, if it isn't
632
633
634 What: /sys/block/<disk>/queue/stable
635 Date: September 2020
636 Contact: linux-block@vger.kernel.org
637 Description:
638 [RW] This file will contain '1
639 while it is being used in a wr
640 this is the case and the kerne
641 page, the kernel will wait for
642 allowing the page to be modifi
643 immediate modification as is n
644 restriction arises when the de
645 times where the same data must
646 example, once to calculate a c
647 the data. If no such restrict
648 '0'. This file is writable fo
649
650 What: /sys/block/<disk>/queue/virt_b
651 Date: April 2021
652 Contact: linux-block@vger.kernel.org
653 Description:
654 [RO] This file shows the I/O s
655 the block device. I/O request
656 between segments wherever eith
657 of the previous segment or the
658 of the current segment is not
659 bytes.
660
661
662 What: /sys/block/<disk>/queue/wbt_la
663 Date: November 2016
664 Contact: linux-block@vger.kernel.org
665 Description:
666 [RW] If the device is register
667 this file shows the target min
668 is exceeded in a given window
669 the writeback throttling will
670 a value of '0' to this file di
671 value of '-1' to this file res
672 setting.
673
674
675 What: /sys/block/<disk>/queue/write_
676 Date: April 2016
677 Contact: linux-block@vger.kernel.org
678 Description:
679 [RW] When read, this file will
680 write back caching enabled or
681 for the former case, and "writ
682 to this file can change the ke
683 doesn't alter the device state
684 safe to toggle the setting fro
685 since that will also eliminate
686 kernel.
687
688
689 What: /sys/block/<disk>/queue/write_
690 Date: January 2012
691 Contact: Martin K. Petersen <martin.pete
692 Description:
693 [RO] Some devices support a wr
694 single data block can be writt
695 contiguous blocks on storage.
696 disk or to initialize drives i
697 write_same_max_bytes indicates
698 a single write same command. I
699 same is not supported by the d
700
701
702 What: /sys/block/<disk>/queue/write_
703 Date: November 2016
704 Contact: Chaitanya Kulkarni <chaitanya.k
705 Description:
706 [RO] Devices that support writ
707 single request can be issued t
708 blocks on storage without havi
709 This can be used to optimize w
710 write_zeroes_max_bytes indicat
711 in a single write zeroes comma
712 0, write zeroes is not support
713
714
715 What: /sys/block/<disk>/queue/zone_a
716 Date: May 2020
717 Contact: linux-block@vger.kernel.org
718 Description:
719 [RO] This is the maximum numbe
720 a sequential zone of a zoned b
721 write operation (REQ_OP_ZONE_A
722 regular block devices.
723
724
725 What: /sys/block/<disk>/queue/zone_w
726 Date: January 2021
727 Contact: linux-block@vger.kernel.org
728 Description:
729 [RO] This indicates the alignm
730 write operations in sequential
731 (devices with a zoned attribut
732 "host-aware"). This value is a
733
734
735 What: /sys/block/<disk>/queue/zoned
736 Date: September 2016
737 Contact: Damien Le Moal <damien.lemoal@w
738 Description:
739 [RO] zoned indicates if the de
740 the zone model of the device i
741 possible values indicated by z
742 devices and "host-aware" or "h
743 devices. The characteristics o
744 zoned block devices are descri
745 Commands) and ZAC (Zoned Devic
746 These standards also define th
747 However, since drive-managed z
748 zone commands, they will be tr
749 zoned will report "none".
750
751
752 What: /sys/block/<disk>/hidden
753 Date: March 2023
754 Contact: linux-block@vger.kernel.org
755 Description:
756 [RO] the block device is hidde
757 can’t be opened from userspa
758 Used for the underlying compon
759
760
761 What: /sys/block/<disk>/stat
762 Date: February 2008
763 Contact: Jerome Marchand <jmarchan@redha
764 Description:
765 The /sys/block/<disk>/stat fil
766 statistics of disk <disk>. The
767
768 == ==========================
769 1 reads completed successful
770 2 reads merged
771 3 sectors read
772 4 time spent reading (ms)
773 5 writes completed
774 6 writes merged
775 7 sectors written
776 8 time spent writing (ms)
777 9 I/Os currently in progress
778 10 time spent doing I/Os (ms)
779 11 weighted time spent doing
780 12 discards completed
781 13 discards merged
782 14 sectors discarded
783 15 time spent discarding (ms)
784 16 flush requests completed
785 17 time spent flushing (ms)
786 == ==========================
787
788 For more details refer Documen
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