470 lines
17 KiB
Plaintext
470 lines
17 KiB
Plaintext
What: /sys/block/<disk>/alignment_offset
|
|
Date: April 2009
|
|
Contact: Martin K. Petersen <martin.petersen@oracle.com>
|
|
Description:
|
|
Storage devices may report a physical block size that is
|
|
bigger than the logical block size (for instance a drive
|
|
with 4KB physical sectors exposing 512-byte logical
|
|
blocks to the operating system). This parameter
|
|
indicates how many bytes the beginning of the device is
|
|
offset from the disk's natural alignment.
|
|
|
|
|
|
What: /sys/block/<disk>/discard_alignment
|
|
Date: May 2011
|
|
Contact: Martin K. Petersen <martin.petersen@oracle.com>
|
|
Description:
|
|
Devices that support discard functionality may
|
|
internally allocate space in units that are bigger than
|
|
the exported logical block size. The discard_alignment
|
|
parameter indicates how many bytes the beginning of the
|
|
device is offset from the internal allocation unit's
|
|
natural alignment.
|
|
|
|
What: /sys/block/<disk>/atomic_write_max_bytes
|
|
Date: February 2024
|
|
Contact: Himanshu Madhani <himanshu.madhani@oracle.com>
|
|
Description:
|
|
[RO] This parameter specifies the maximum atomic write
|
|
size reported by the device. This parameter is relevant
|
|
for merging of writes, where a merged atomic write
|
|
operation must not exceed this number of bytes.
|
|
This parameter may be greater than the value in
|
|
atomic_write_unit_max_bytes as
|
|
atomic_write_unit_max_bytes will be rounded down to a
|
|
power-of-two and atomic_write_unit_max_bytes may also be
|
|
limited by some other queue limits, such as max_segments.
|
|
This parameter - along with atomic_write_unit_min_bytes
|
|
and atomic_write_unit_max_bytes - will not be larger than
|
|
max_hw_sectors_kb, but may be larger than max_sectors_kb.
|
|
|
|
|
|
What: /sys/block/<disk>/atomic_write_unit_min_bytes
|
|
Date: February 2024
|
|
Contact: Himanshu Madhani <himanshu.madhani@oracle.com>
|
|
Description:
|
|
[RO] This parameter specifies the smallest block which can
|
|
be written atomically with an atomic write operation. All
|
|
atomic write operations must begin at a
|
|
atomic_write_unit_min boundary and must be multiples of
|
|
atomic_write_unit_min. This value must be a power-of-two.
|
|
|
|
|
|
What: /sys/block/<disk>/atomic_write_unit_max_bytes
|
|
Date: February 2024
|
|
Contact: Himanshu Madhani <himanshu.madhani@oracle.com>
|
|
Description:
|
|
[RO] This parameter defines the largest block which can be
|
|
written atomically with an atomic write operation. This
|
|
value must be a multiple of atomic_write_unit_min and must
|
|
be a power-of-two. This value will not be larger than
|
|
atomic_write_max_bytes.
|
|
|
|
|
|
What: /sys/block/<disk>/atomic_write_boundary_bytes
|
|
Date: February 2024
|
|
Contact: Himanshu Madhani <himanshu.madhani@oracle.com>
|
|
Description:
|
|
[RO] A device may need to internally split an atomic write I/O
|
|
which straddles a given logical block address boundary. This
|
|
parameter specifies the size in bytes of the atomic boundary if
|
|
one is reported by the device. This value must be a
|
|
power-of-two and at least the size as in
|
|
atomic_write_unit_max_bytes.
|
|
Any attempt to merge atomic write I/Os must not result in a
|
|
merged I/O which crosses this boundary (if any).
|
|
|
|
|
|
What: /sys/block/<disk>/diskseq
|
|
Date: February 2021
|
|
Contact: Matteo Croce <mcroce@microsoft.com>
|
|
Description:
|
|
The /sys/block/<disk>/diskseq files reports the disk
|
|
sequence number, which is a monotonically increasing
|
|
number assigned to every drive.
|
|
Some devices, like the loop device, refresh such number
|
|
every time the backing file is changed.
|
|
The value type is 64 bit unsigned.
|
|
|
|
|
|
What: /sys/block/<disk>/integrity/device_is_integrity_capable
|
|
Date: July 2014
|
|
Contact: Martin K. Petersen <martin.petersen@oracle.com>
|
|
Description:
|
|
Indicates whether a storage device is capable of storing
|
|
integrity metadata. Set if the device is T10 PI-capable.
|
|
|
|
|
|
What: /sys/block/<disk>/integrity/format
|
|
Date: June 2008
|
|
Contact: Martin K. Petersen <martin.petersen@oracle.com>
|
|
Description:
|
|
Metadata format for integrity capable block device.
|
|
E.g. T10-DIF-TYPE1-CRC.
|
|
|
|
|
|
What: /sys/block/<disk>/integrity/protection_interval_bytes
|
|
Date: July 2015
|
|
Contact: Martin K. Petersen <martin.petersen@oracle.com>
|
|
Description:
|
|
Describes the number of data bytes which are protected
|
|
by one integrity tuple. Typically the device's logical
|
|
block size.
|
|
|
|
|
|
What: /sys/block/<disk>/integrity/read_verify
|
|
Date: June 2008
|
|
Contact: Martin K. Petersen <martin.petersen@oracle.com>
|
|
Description:
|
|
Indicates whether the block layer should verify the
|
|
integrity of read requests serviced by devices that
|
|
support sending integrity metadata.
|
|
|
|
|
|
What: /sys/block/<disk>/integrity/tag_size
|
|
Date: June 2008
|
|
Contact: Martin K. Petersen <martin.petersen@oracle.com>
|
|
Description:
|
|
Number of bytes of integrity tag space available per
|
|
512 bytes of data.
|
|
|
|
|
|
What: /sys/block/<disk>/integrity/write_generate
|
|
Date: June 2008
|
|
Contact: Martin K. Petersen <martin.petersen@oracle.com>
|
|
Description:
|
|
Indicates whether the block layer should automatically
|
|
generate checksums for write requests bound for
|
|
devices that support receiving integrity metadata.
|
|
|
|
|
|
What: /sys/block/<disk>/partscan
|
|
Date: May 2024
|
|
Contact: Christoph Hellwig <hch@lst.de>
|
|
Description:
|
|
The /sys/block/<disk>/partscan files reports if partition
|
|
scanning is enabled for the disk. It returns "1" if partition
|
|
scanning is enabled, or "0" if not. The value type is a 32-bit
|
|
unsigned integer, but only "0" and "1" are valid values.
|
|
|
|
|
|
What: /sys/block/<disk>/<partition>/alignment_offset
|
|
Date: April 2009
|
|
Contact: Martin K. Petersen <martin.petersen@oracle.com>
|
|
Description:
|
|
Storage devices may report a physical block size that is
|
|
bigger than the logical block size (for instance a drive
|
|
with 4KB physical sectors exposing 512-byte logical
|
|
blocks to the operating system). This parameter
|
|
indicates how many bytes the beginning of the partition
|
|
is offset from the disk's natural alignment.
|
|
|
|
|
|
What: /sys/block/<disk>/<partition>/discard_alignment
|
|
Date: May 2011
|
|
Contact: Martin K. Petersen <martin.petersen@oracle.com>
|
|
Description:
|
|
Devices that support discard functionality may
|
|
internally allocate space in units that are bigger than
|
|
the exported logical block size. The discard_alignment
|
|
parameter indicates how many bytes the beginning of the
|
|
partition is offset from the internal allocation unit's
|
|
natural alignment.
|
|
|
|
|
|
What: /sys/block/<disk>/<partition>/stat
|
|
Date: February 2008
|
|
Contact: Jerome Marchand <jmarchan@redhat.com>
|
|
Description:
|
|
The /sys/block/<disk>/<partition>/stat files display the
|
|
I/O statistics of partition <partition>. The format is the
|
|
same as the format of /sys/block/<disk>/stat.
|
|
|
|
|
|
What: /sys/block/<disk>/queue/chunk_sectors
|
|
Date: September 2016
|
|
Contact: Hannes Reinecke <hare@suse.com>
|
|
Description:
|
|
chunk_sectors has different meaning depending on the type
|
|
of the disk. For a RAID device (dm-raid), chunk_sectors
|
|
indicates the size in 512B sectors of the RAID volume
|
|
stripe segment. For a zoned block device, either
|
|
host-aware or host-managed, chunk_sectors indicates the
|
|
size in 512B sectors of the zones of the device, with
|
|
the eventual exception of the last zone of the device
|
|
which may be smaller.
|
|
|
|
What: /sys/block/<disk>/queue/crypto/
|
|
Date: February 2022
|
|
Contact: linux-block@vger.kernel.org
|
|
Description:
|
|
The presence of this subdirectory of /sys/block/<disk>/queue/
|
|
indicates that the device supports inline encryption. This
|
|
subdirectory contains files which describe the inline encryption
|
|
capabilities of the device. For more information about inline
|
|
encryption, refer to Documentation/block/inline-encryption.rst.
|
|
|
|
|
|
What: /sys/block/<disk>/queue/crypto/max_dun_bits
|
|
Date: February 2022
|
|
Contact: linux-block@vger.kernel.org
|
|
Description:
|
|
[RO] This file shows the maximum length, in bits, of data unit
|
|
numbers accepted by the device in inline encryption requests.
|
|
|
|
|
|
What: /sys/block/<disk>/queue/crypto/modes/<mode>
|
|
Date: February 2022
|
|
Contact: linux-block@vger.kernel.org
|
|
Description:
|
|
[RO] For each crypto mode (i.e., encryption/decryption
|
|
algorithm) the device supports with inline encryption, a file
|
|
will exist at this location. It will contain a hexadecimal
|
|
number that is a bitmask of the supported data unit sizes, in
|
|
bytes, for that crypto mode.
|
|
|
|
Currently, the crypto modes that may be supported are:
|
|
|
|
* AES-256-XTS
|
|
* AES-128-CBC-ESSIV
|
|
* Adiantum
|
|
|
|
For example, if a device supports AES-256-XTS inline encryption
|
|
with data unit sizes of 512 and 4096 bytes, the file
|
|
/sys/block/<disk>/queue/crypto/modes/AES-256-XTS will exist and
|
|
will contain "0x1200".
|
|
|
|
|
|
What: /sys/block/<disk>/queue/crypto/num_keyslots
|
|
Date: February 2022
|
|
Contact: linux-block@vger.kernel.org
|
|
Description:
|
|
[RO] This file shows the number of keyslots the device has for
|
|
use with inline encryption.
|
|
|
|
|
|
What: /sys/block/<disk>/queue/discard_granularity
|
|
Date: May 2011
|
|
Contact: Martin K. Petersen <martin.petersen@oracle.com>
|
|
Description:
|
|
Devices that support discard functionality may
|
|
internally allocate space using units that are bigger
|
|
than the logical block size. The discard_granularity
|
|
parameter indicates the size of the internal allocation
|
|
unit in bytes if reported by the device. Otherwise the
|
|
discard_granularity will be set to match the device's
|
|
physical block size. A discard_granularity of 0 means
|
|
that the device does not support discard functionality.
|
|
|
|
|
|
What: /sys/block/<disk>/queue/discard_max_bytes
|
|
Date: May 2011
|
|
Contact: Martin K. Petersen <martin.petersen@oracle.com>
|
|
Description:
|
|
Devices that support discard functionality may have
|
|
internal limits on the number of bytes that can be
|
|
trimmed or unmapped in a single operation. Some storage
|
|
protocols also have inherent limits on the number of
|
|
blocks that can be described in a single command. The
|
|
discard_max_bytes parameter is set by the device driver
|
|
to the maximum number of bytes that can be discarded in
|
|
a single operation. Discard requests issued to the
|
|
device must not exceed this limit. A discard_max_bytes
|
|
value of 0 means that the device does not support
|
|
discard functionality.
|
|
|
|
|
|
What: /sys/block/<disk>/queue/discard_zeroes_data
|
|
Date: May 2011
|
|
Contact: Martin K. Petersen <martin.petersen@oracle.com>
|
|
Description:
|
|
Will always return 0. Don't rely on any specific behavior
|
|
for discards, and don't read this file.
|
|
|
|
What: /sys/block/<disk>/queue/dma_alignment
|
|
Date: May 2022
|
|
Contact: linux-block@vger.kernel.org
|
|
Description:
|
|
Reports the alignment that user space addresses must have to be
|
|
used for raw block device access with O_DIRECT and other driver
|
|
specific passthrough mechanisms.
|
|
|
|
What: /sys/block/<disk>/queue/io_timeout
|
|
Date: November 2018
|
|
Contact: Weiping Zhang <zhangweiping@didiglobal.com>
|
|
Description:
|
|
io_timeout is the request timeout in milliseconds. If a request
|
|
does not complete in this time then the block driver timeout
|
|
handler is invoked. That timeout handler can decide to retry
|
|
the request, to fail it or to start a device recovery strategy.
|
|
|
|
|
|
What: /sys/block/<disk>/queue/logical_block_size
|
|
Date: May 2009
|
|
Contact: Martin K. Petersen <martin.petersen@oracle.com>
|
|
Description:
|
|
This is the smallest unit the storage device can
|
|
address. It is typically 512 bytes.
|
|
|
|
|
|
What: /sys/block/<disk>/queue/max_active_zones
|
|
Date: July 2020
|
|
Contact: Niklas Cassel <niklas.cassel@wdc.com>
|
|
Description:
|
|
For zoned block devices (zoned attribute indicating
|
|
"host-managed" or "host-aware"), the sum of zones belonging to
|
|
any of the zone states: EXPLICIT OPEN, IMPLICIT OPEN or CLOSED,
|
|
is limited by this value. If this value is 0, there is no limit.
|
|
|
|
|
|
What: /sys/block/<disk>/queue/max_open_zones
|
|
Date: July 2020
|
|
Contact: Niklas Cassel <niklas.cassel@wdc.com>
|
|
Description:
|
|
For zoned block devices (zoned attribute indicating
|
|
"host-managed" or "host-aware"), the sum of zones belonging to
|
|
any of the zone states: EXPLICIT OPEN or IMPLICIT OPEN,
|
|
is limited by this value. If this value is 0, there is no limit.
|
|
|
|
|
|
What: /sys/block/<disk>/queue/minimum_io_size
|
|
Date: April 2009
|
|
Contact: Martin K. Petersen <martin.petersen@oracle.com>
|
|
Description:
|
|
Storage devices may report a granularity or preferred
|
|
minimum I/O size which is the smallest request the
|
|
device can perform without incurring a performance
|
|
penalty. For disk drives this is often the physical
|
|
block size. For RAID arrays it is often the stripe
|
|
chunk size. A properly aligned multiple of
|
|
minimum_io_size is the preferred request size for
|
|
workloads where a high number of I/O operations is
|
|
desired.
|
|
|
|
|
|
What: /sys/block/<disk>/queue/nomerges
|
|
Date: January 2010
|
|
Contact: linux-block@vger.kernel.org
|
|
Description:
|
|
Standard I/O elevator operations include attempts to
|
|
merge contiguous I/Os. For known random I/O loads these
|
|
attempts will always fail and result in extra cycles
|
|
being spent in the kernel. This allows one to turn off
|
|
this behavior on one of two ways: When set to 1, complex
|
|
merge checks are disabled, but the simple one-shot merges
|
|
with the previous I/O request are enabled. When set to 2,
|
|
all merge tries are disabled. The default value is 0 -
|
|
which enables all types of merge tries.
|
|
|
|
|
|
What: /sys/block/<disk>/queue/nr_zones
|
|
Date: November 2018
|
|
Contact: Damien Le Moal <damien.lemoal@wdc.com>
|
|
Description:
|
|
nr_zones indicates the total number of zones of a zoned block
|
|
device ("host-aware" or "host-managed" zone model). For regular
|
|
block devices, the value is always 0.
|
|
|
|
|
|
What: /sys/block/<disk>/queue/optimal_io_size
|
|
Date: April 2009
|
|
Contact: Martin K. Petersen <martin.petersen@oracle.com>
|
|
Description:
|
|
Storage devices may report an optimal I/O size, which is
|
|
the device's preferred unit for sustained I/O. This is
|
|
rarely reported for disk drives. For RAID arrays it is
|
|
usually the stripe width or the internal track size. A
|
|
properly aligned multiple of optimal_io_size is the
|
|
preferred request size for workloads where sustained
|
|
throughput is desired. If no optimal I/O size is
|
|
reported this file contains 0.
|
|
|
|
|
|
What: /sys/block/<disk>/queue/physical_block_size
|
|
Date: May 2009
|
|
Contact: Martin K. Petersen <martin.petersen@oracle.com>
|
|
Description:
|
|
This is the smallest unit a physical storage device can
|
|
write atomically. It is usually the same as the logical
|
|
block size but may be bigger. One example is SATA
|
|
drives with 4KB sectors that expose a 512-byte logical
|
|
block size to the operating system. For stacked block
|
|
devices the physical_block_size variable contains the
|
|
maximum physical_block_size of the component devices.
|
|
|
|
|
|
What: /sys/block/<disk>/queue/write_same_max_bytes
|
|
Date: January 2012
|
|
Contact: Martin K. Petersen <martin.petersen@oracle.com>
|
|
Description:
|
|
Some devices support a write same operation in which a
|
|
single data block can be written to a range of several
|
|
contiguous blocks on storage. This can be used to wipe
|
|
areas on disk or to initialize drives in a RAID
|
|
configuration. write_same_max_bytes indicates how many
|
|
bytes can be written in a single write same command. If
|
|
write_same_max_bytes is 0, write same is not supported
|
|
by the device.
|
|
|
|
|
|
What: /sys/block/<disk>/queue/write_zeroes_max_bytes
|
|
Date: November 2016
|
|
Contact: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
|
|
Description:
|
|
Devices that support write zeroes operation in which a
|
|
single request can be issued to zero out the range of
|
|
contiguous blocks on storage without having any payload
|
|
in the request. This can be used to optimize writing zeroes
|
|
to the devices. write_zeroes_max_bytes indicates how many
|
|
bytes can be written in a single write zeroes command. If
|
|
write_zeroes_max_bytes is 0, write zeroes is not supported
|
|
by the device.
|
|
|
|
|
|
What: /sys/block/<disk>/queue/zoned
|
|
Date: September 2016
|
|
Contact: Damien Le Moal <damien.lemoal@wdc.com>
|
|
Description:
|
|
zoned indicates if the device is a zoned block device
|
|
and the zone model of the device if it is indeed zoned.
|
|
The possible values indicated by zoned are "none" for
|
|
regular block devices and "host-aware" or "host-managed"
|
|
for zoned block devices. The characteristics of
|
|
host-aware and host-managed zoned block devices are
|
|
described in the ZBC (Zoned Block Commands) and ZAC
|
|
(Zoned Device ATA Command Set) standards. These standards
|
|
also define the "drive-managed" zone model. However,
|
|
since drive-managed zoned block devices do not support
|
|
zone commands, they will be treated as regular block
|
|
devices and zoned will report "none".
|
|
|
|
|
|
What: /sys/block/<disk>/stat
|
|
Date: February 2008
|
|
Contact: Jerome Marchand <jmarchan@redhat.com>
|
|
Description:
|
|
The /sys/block/<disk>/stat files displays the I/O
|
|
statistics of disk <disk>. They contain 11 fields:
|
|
|
|
== ==============================================
|
|
1 reads completed successfully
|
|
2 reads merged
|
|
3 sectors read
|
|
4 time spent reading (ms)
|
|
5 writes completed
|
|
6 writes merged
|
|
7 sectors written
|
|
8 time spent writing (ms)
|
|
9 I/Os currently in progress
|
|
10 time spent doing I/Os (ms)
|
|
11 weighted time spent doing I/Os (ms)
|
|
12 discards completed
|
|
13 discards merged
|
|
14 sectors discarded
|
|
15 time spent discarding (ms)
|
|
16 flush requests completed
|
|
17 time spent flushing (ms)
|
|
== ==============================================
|
|
|
|
For more details refer Documentation/admin-guide/iostats.rst
|