sysfs-block - OpenGrok cross reference for /linux-6.12.1/Documentation/ABI/stable/sysfs-block

1 What:		/sys/block/<disk>/alignment_offset
5 		Storage devices may report a physical block size that is
6 		bigger than the logical block size (for instance a drive
7 		with 4KB physical sectors exposing 512-byte logical
13 What:		/sys/block/<disk>/discard_alignment
19 		the exported logical block size. The discard_alignment
24 What:		/sys/block/<disk>/atomic_write_max_bytes
29 		size reported by the device. This parameter is relevant
35 		power-of-two and atomic_write_unit_max_bytes may also be
37 		This parameter - along with atomic_write_unit_min_bytes
38 		and atomic_write_unit_max_bytes - will not be larger than
42 What:		/sys/block/<disk>/atomic_write_unit_min_bytes
46 		[RO] This parameter specifies the smallest block which can
50 		atomic_write_unit_min. This value must be a power-of-two.
53 What:		/sys/block/<disk>/atomic_write_unit_max_bytes
57 		[RO] This parameter defines the largest block which can be
60 		be a power-of-two. This value will not be larger than
64 What:		/sys/block/<disk>/atomic_write_boundary_bytes
69 		which straddles a given logical block address boundary. This
70 		parameter specifies the size in bytes of the atomic boundary if
72 		power-of-two and at least the size as in
78 What:		/sys/block/<disk>/diskseq
82 		The /sys/block/<disk>/diskseq files reports the disk
90 What:		/sys/block/<disk>/inflight
96 		than the number of requests queued in the block device queue.
100 		Cf. Documentation/block/stat.rst which contains a single value for
102 		This is related to /sys/block/<disk>/queue/nr_requests
106 What:		/sys/block/<disk>/integrity/device_is_integrity_capable
111 		integrity metadata. Set if the device is T10 PI-capable.
114 What:		/sys/block/<disk>/integrity/format
118 		Metadata format for integrity capable block device.
119 		E.g. T10-DIF-TYPE1-CRC.
122 What:		/sys/block/<disk>/integrity/protection_interval_bytes
128 		block size.
131 What:		/sys/block/<disk>/integrity/read_verify
135 		Indicates whether the block layer should verify the
140 What:		/sys/block/<disk>/integrity/tag_size
148 What:		/sys/block/<disk>/integrity/write_generate
152 		Indicates whether the block layer should automatically
157 What:		/sys/block/<disk>/partscan
161 		The /sys/block/<disk>/partscan files reports if partition
163 		scanning is enabled, or "0" if not.  The value type is a 32-bit
167 What:		/sys/block/<disk>/<partition>/alignment_offset
171 		Storage devices may report a physical block size that is
172 		bigger than the logical block size (for instance a drive
173 		with 4KB physical sectors exposing 512-byte logical
179 What:		/sys/block/<disk>/<partition>/discard_alignment
185 		the exported logical block size. The discard_alignment
191 What:		/sys/block/<disk>/<partition>/stat
195 		The /sys/block/<disk>/<partition>/stat files display the
197 		same as the format of /sys/block/<disk>/stat.
200 What:		/sys/block/<disk>/queue/add_random
202 Contact:	linux-block@vger.kernel.org
208 What:		/sys/block/<disk>/queue/chunk_sectors
213 		of the disk. For a RAID device (dm-raid), chunk_sectors
214 		indicates the size in 512B sectors of the RAID volume stripe
215 		segment. For a zoned block device, either host-aware or
216 		host-managed, chunk_sectors indicates the size in 512B sectors
221 What:		/sys/block/<disk>/queue/crypto/
223 Contact:	linux-block@vger.kernel.org
225 		The presence of this subdirectory of /sys/block/<disk>/queue/
229 		encryption, refer to Documentation/block/inline-encryption.rst.
232 What:		/sys/block/<disk>/queue/crypto/max_dun_bits
234 Contact:	linux-block@vger.kernel.org
240 What:		/sys/block/<disk>/queue/crypto/modes/<mode>
242 Contact:	linux-block@vger.kernel.org
252 		   * AES-256-XTS
253 		   * AES-128-CBC-ESSIV
256 		For example, if a device supports AES-256-XTS inline encryption
258 		/sys/block/<disk>/queue/crypto/modes/AES-256-XTS will exist and
262 What:		/sys/block/<disk>/queue/crypto/num_keyslots
264 Contact:	linux-block@vger.kernel.org
270 What:		/sys/block/<disk>/queue/dax
272 Contact:	linux-block@vger.kernel.org
275 		Access (DAX), used by CPU-addressable storage to bypass the
279 What:		/sys/block/<disk>/queue/discard_granularity
285 		block size. The discard_granularity parameter indicates the size
288 		the device's physical block size. A discard_granularity of 0
292 What:		/sys/block/<disk>/queue/discard_max_bytes
304 What:		/sys/block/<disk>/queue/discard_max_hw_bytes
306 Contact:	linux-block@vger.kernel.org
318 What:		/sys/block/<disk>/queue/discard_zeroes_data
326 What:		/sys/block/<disk>/queue/dma_alignment
328 Contact:	linux-block@vger.kernel.org
331 		used for raw block device access with O_DIRECT and other driver
335 What:		/sys/block/<disk>/queue/fua
337 Contact:	linux-block@vger.kernel.org
339 		[RO] Whether or not the block driver supports the FUA flag for
345 What:		/sys/block/<disk>/queue/hw_sector_size
347 Contact:	linux-block@vger.kernel.org
349 		[RO] This is the hardware sector size of the device, in bytes.
352 What:		/sys/block/<disk>/queue/independent_access_ranges/
354 Contact:	linux-block@vger.kernel.org
356 		[RO] The presence of this sub-directory of the
357 		/sys/block/xxx/queue/ directory indicates that the device is
359 		in parallel. For instance, single LUN multi-actuator hard-disks
368 		the range.  For example, a dual-actuator hard-disk will have the
371 			$ tree /sys/block/<disk>/queue/independent_access_ranges/
372 			/sys/block/<disk>/queue/independent_access_ranges/
373 			|-- 0
374 			|   |-- nr_sectors
375 			|   `-- sector
376 			`-- 1
377 			    |-- nr_sectors
378 			    `-- sector
381 		regardless of the actual block size of the device. Independent
388 What:		/sys/block/<disk>/queue/io_poll
390 Contact:	linux-block@vger.kernel.org
394 		for this device.  Writing any non-zero value will enable this
398 What:		/sys/block/<disk>/queue/io_poll_delay
400 Contact:	linux-block@vger.kernel.org
403 		performed.  It is now fixed to -1, which is classic polling.
409 What:		/sys/block/<disk>/queue/io_timeout
414 		request does not complete in this time then the block driver
420 What:		/sys/block/<disk>/queue/iostats
422 Contact:	linux-block@vger.kernel.org
428 What:		/sys/block/<disk>/queue/logical_block_size
436 What:		/sys/block/<disk>/queue/max_active_zones
440 		[RO] For zoned block devices (zoned attribute indicating
441 		"host-managed" or "host-aware"), the sum of zones belonging to
450 What:		/sys/block/<disk>/queue/max_discard_segments
452 Contact:	linux-block@vger.kernel.org
458 What:		/sys/block/<disk>/queue/max_hw_sectors_kb
460 Contact:	linux-block@vger.kernel.org
466 What:		/sys/block/<disk>/queue/max_integrity_segments
468 Contact:	linux-block@vger.kernel.org
471 		with integrity data that will be submitted by the block layer
472 		core to the associated block driver.
475 What:		/sys/block/<disk>/queue/max_open_zones
479 		[RO] For zoned block devices (zoned attribute indicating
480 		"host-managed" or "host-aware"), the sum of zones belonging to
485 What:		/sys/block/<disk>/queue/max_sectors_kb
487 Contact:	linux-block@vger.kernel.org
489 		[RW] This is the maximum number of kilobytes that the block
491 		or equal to the maximum size allowed by the hardware. Write 0
495 What:		/sys/block/<disk>/queue/max_segment_size
497 Contact:	linux-block@vger.kernel.org
499 		[RO] Maximum size in bytes of a single element in a DMA
503 What:		/sys/block/<disk>/queue/max_segments
505 Contact:	linux-block@vger.kernel.org
508 		that is submitted to the associated block driver.
511 What:		/sys/block/<disk>/queue/minimum_io_size
516 		minimum I/O size which is the smallest request the device can
518 		drives this is often the physical block size.  For RAID arrays
519 		it is often the stripe chunk size.  A properly aligned multiple
520 		of minimum_io_size is the preferred request size for workloads
524 What:		/sys/block/<disk>/queue/nomerges
526 Contact:	linux-block@vger.kernel.org
533 		simple one-shot merges with the previous I/O request are
535 		default value is 0 - which enables all types of merge tries.
538 What:		/sys/block/<disk>/queue/nr_requests
540 Contact:	linux-block@vger.kernel.org
543 		block layer for read or write requests. Note that the total
550 		each such per-block-cgroup request pool.  IOW, if there are N
551 		block cgroups, each request queue may have up to N request
555 What:		/sys/block/<disk>/queue/nr_zones
560 		block device ("host-aware" or "host-managed" zone model). For
561 		regular block devices, the value is always 0.
564 What:		/sys/block/<disk>/queue/optimal_io_size
568 		[RO] Storage devices may report an optimal I/O size, which is
571 		stripe width or the internal track size.  A properly aligned
572 		multiple of optimal_io_size is the preferred request size for
574 		I/O size is reported this file contains 0.
577 What:		/sys/block/<disk>/queue/physical_block_size
582 		write atomically.  It is usually the same as the logical block
583 		size but may be bigger.  One example is SATA drives with 4KB
584 		sectors that expose a 512-byte logical block size to the
585 		operating system.  For stacked block devices the
590 What:		/sys/block/<disk>/queue/read_ahead_kb
592 Contact:	linux-block@vger.kernel.org
594 		[RW] Maximum number of kilobytes to read-ahead for filesystems
595 		on this block device.
597 		For MADV_HUGEPAGE, the readahead size may exceed this setting
598 		since its granularity is based on the hugepage size.
601 What:		/sys/block/<disk>/queue/rotational
603 Contact:	linux-block@vger.kernel.org
606 		type or non-rotational type.
609 What:		/sys/block/<disk>/queue/rq_affinity
611 Contact:	linux-block@vger.kernel.org
613 		[RW] If this option is '1', the block layer will migrate request
624 What:		/sys/block/<disk>/queue/scheduler
626 Contact:	linux-block@vger.kernel.org
629 		IO schedulers for this block device. The currently active IO
631 		scheduler name to this file will switch control of this block
637 What:		/sys/block/<disk>/queue/stable_writes
639 Contact:	linux-block@vger.kernel.org
648 		times where the same data must be seen every time -- for
653 What:		/sys/block/<disk>/queue/virt_boundary_mask
655 Contact:	linux-block@vger.kernel.org
658 		the block device.  I/O requests to this device will be split
665 What:		/sys/block/<disk>/queue/wbt_lat_usec
667 Contact:	linux-block@vger.kernel.org
674 		value of '-1' to this file resets the value to the default
678 What:		/sys/block/<disk>/queue/write_cache
680 Contact:	linux-block@vger.kernel.org
692 What:		/sys/block/<disk>/queue/write_same_max_bytes
697 		single data block can be written to a range of several
705 What:		/sys/block/<disk>/queue/write_zeroes_max_bytes
718 What:		/sys/block/<disk>/queue/zone_append_max_bytes
720 Contact:	linux-block@vger.kernel.org
723 		a sequential zone of a zoned block device using a zone append
725 		regular block devices.
728 What:		/sys/block/<disk>/queue/zone_write_granularity
730 Contact:	linux-block@vger.kernel.org
733 		write operations in sequential zones of zoned block devices
734 		(devices with a zoned attributed that reports "host-managed" or
735 		"host-aware"). This value is always 0 for regular block devices.
738 What:		/sys/block/<disk>/queue/zoned
742 		[RO] zoned indicates if the device is a zoned block device and
744 		possible values indicated by zoned are "none" for regular block
745 		devices and "host-aware" or "host-managed" for zoned block
746 		devices. The characteristics of host-aware and host-managed
747 		zoned block devices are described in the ZBC (Zoned Block
749 		These standards also define the "drive-managed" zone model.
750 		However, since drive-managed zoned block devices do not support
751 		zone commands, they will be treated as regular block devices and
755 What:		/sys/block/<disk>/hidden
757 Contact:	linux-block@vger.kernel.org
759 		[RO] the block device is hidden. it doesn’t produce events, and
764 What:		/sys/block/<disk>/stat
768 		The /sys/block/<disk>/stat files displays the I/O
791 		For more details refer Documentation/admin-guide/iostats.rst