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