blockdevice

package
v0.8.0 Latest Latest
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 Go to latest Published: Jul 20, 2022 License: Apache-2.0 Imports: 7 Imported by: 13

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Variables

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Functions

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Types

type BlockQueueStats added in v0.1.0 

type BlockQueueStats struct {
	// AddRandom is the status of a disk entropy (1 is on, 0 is off).
	AddRandom uint64
	// Dax indicates whether the device supports Direct Access (DAX) (1 is on, 0 is off).
	DAX uint64
	// DiscardGranularity is the size of internal allocation of the device in bytes, 0 means device
	// does not support the discard functionality.
	DiscardGranularity uint64
	// DiscardMaxHWBytes is the hardware maximum number of bytes that can be discarded in a single operation,
	// 0 means device does not support the discard functionality.
	DiscardMaxHWBytes uint64
	// DiscardMaxBytes is the software maximum number of bytes that can be discarded in a single operation.
	DiscardMaxBytes uint64
	// HWSectorSize is the sector size of the device, in bytes.
	HWSectorSize uint64
	// IOPoll indicates if polling is enabled (1 is on, 0 is off).
	IOPoll uint64
	// IOPollDelay indicates how polling will be performed, -1 for classic polling, 0 for hybrid polling,
	// with greater than 0 the kernel will put process issuing IO to sleep for this amount of time in
	// microseconds before entering classic polling.
	IOPollDelay int64
	// IOTimeout is the request timeout in milliseconds.
	IOTimeout uint64
	// IOStats indicates if iostats accounting is used for the disk (1 is on, 0 is off).
	IOStats uint64
	// LogicalBlockSize is the logical block size of the device, in bytes.
	LogicalBlockSize uint64
	// MaxHWSectorsKB is the maximum number of kilobytes supported in a single data transfer.
	MaxHWSectorsKB uint64
	// MaxIntegritySegments is the max limit of integrity segments as set by block layer which a hardware controller
	// can handle.
	MaxIntegritySegments uint64
	// MaxSectorsKB is the maximum number of kilobytes that the block layer will allow for a filesystem request.
	MaxSectorsKB uint64
	// MaxSegments is the number of segments on the device.
	MaxSegments uint64
	// MaxSegmentsSize is the maximum segment size of the device.
	MaxSegmentSize uint64
	// MinimumIOSize is the smallest preferred IO size reported by the device.
	MinimumIOSize uint64
	// NoMerges shows the lookup logic involved with IO merging requests in the block layer. 0 all merges are
	// enabled, 1 only simple one hit merges are tried, 2 no merge algorithms will be tried.
	NoMerges uint64
	// NRRequests is the number of how many requests may be allocated in the block layer for read or write requests.
	NRRequests uint64
	// OptimalIOSize is the optimal IO size reported by the device.
	OptimalIOSize uint64
	// PhysicalBlockSize is the physical block size of device, in bytes.
	PhysicalBlockSize uint64
	// ReadAHeadKB is the maximum number of kilobytes to read-ahead for filesystems on this block device.
	ReadAHeadKB uint64
	// Rotational indicates if the device is of rotational type or non-rotational type.
	Rotational uint64
	// RQAffinity indicates affinity policy of device, if 1 the block layer will migrate request completions to the
	// cpu “group” that originally submitted the request, if 2 forces the completion to run on the requesting cpu.
	RQAffinity uint64
	// SchedulerList contains list of available schedulers for this block device.
	SchedulerList []string
	// SchedulerCurrent is the current scheduler for this block device.
	SchedulerCurrent string
	// WriteCache shows the type of cache for block device, "write back" or "write through".
	WriteCache string
	// WriteSameMaxBytes is the number of bytes the device can write in a single write-same command.
	// A value of ‘0’ means write-same is not supported by this device.
	WriteSameMaxBytes uint64
	// WBTLatUSec is the target minimum read latency, 0 means feature is disables.
	WBTLatUSec int64
	// ThrottleSampleTime is the time window that blk-throttle samples data, in millisecond. Optional
	// exists only if CONFIG_BLK_DEV_THROTTLING_LOW is enabled.
	ThrottleSampleTime *uint64
	// Zoned indicates if the device is a zoned block device and the zone model of the device if it is indeed zoned.
	// Possible values are: none, host-aware, host-managed for zoned block devices.
	Zoned string
	// NRZones indicates the total number of zones of the device, always zero for regular block devices.
	NRZones uint64
	// ChunksSectors for RAID is the size in 512B sectors of the RAID volume stripe segment,
	// for zoned host device is the size in 512B sectors.
	ChunkSectors uint64
	// FUA indicates whether the device supports Force Unit Access for write requests.
	FUA uint64
	// MaxDiscardSegments is the maximum number of DMA entries in a discard request.
	MaxDiscardSegments uint64
	// WriteZeroesMaxBytes the maximum number of bytes that can be zeroed at once.
	// The value 0 means that REQ_OP_WRITE_ZEROES is not supported.
	WriteZeroesMaxBytes uint64
}

BlockQueueStats models the queue files that are located in the sysfs tree for each block device and described in the kernel documentation: https://www.kernel.org/doc/Documentation/block/queue-sysfs.txt https://www.kernel.org/doc/html/latest/block/queue-sysfs.html

type DeviceMapperInfo added in v0.8.0 

type DeviceMapperInfo struct {
	// Name is the string containing mapped device name.
	Name string
	// RqBasedSeqIOMergeDeadline determines how long (in microseconds) a request that is a reasonable merge
	// candidate can be queued on the request queue.
	RqBasedSeqIOMergeDeadline uint64
	// Suspended indicates if the device is suspended (1 is on, 0 is off).
	Suspended uint64
	// UseBlkMQ indicates if the device is using the request-based blk-mq I/O path mode (1 is on, 0 is off).
	UseBlkMQ uint64
	// UUID is the DM-UUID string or empty string if DM-UUID is not set.
	UUID string
}

DeviceMapperInfo models the devicemapper files that are located in the sysfs tree for each block device and described in the kernel documentation: https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-block-dm

type Diskstats 

type Diskstats struct {
	Info
	IOStats
	// IoStatsCount contains the number of io stats read. For kernel versions 5.5+,
	// there should be 20 fields read. For kernel versions 4.18+,
	// there should be 18 fields read. For earlier kernel versions this
	// will be 14 because the discard values are not available.
	IoStatsCount int
}

Diskstats combines the device Info and IOStats.

type FS 

type FS struct {
	// contains filtered or unexported fields
}

FS represents the pseudo-filesystems proc and sys, which provides an interface to kernel data structures.

func NewDefaultFS added in v0.0.2 

func NewDefaultFS() (FS, error)

NewDefaultFS returns a new blockdevice fs using the default mountPoints for proc and sys. It will error if either of these mount points can't be read.

func NewFS 

func NewFS(procMountPoint string, sysMountPoint string) (FS, error)

NewFS returns a new blockdevice fs using the given mountPoints for proc and sys. It will error if either of these mount points can't be read.

func (FS) ProcDiskstats 

func (fs FS) ProcDiskstats() ([]Diskstats, error)

ProcDiskstats reads the diskstats file and returns an array of Diskstats (one per line/device).

func (FS) SysBlockDeviceMapperInfo added in v0.8.0 

func (fs FS) SysBlockDeviceMapperInfo(device string) (DeviceMapperInfo, error)

func (FS) SysBlockDeviceQueueStats added in v0.1.0 

func (fs FS) SysBlockDeviceQueueStats(device string) (BlockQueueStats, error)

SysBlockDeviceQueueStats returns stats for /sys/block/xxx/queue where xxx is a device name.

func (FS) SysBlockDeviceStat 

func (fs FS) SysBlockDeviceStat(device string) (IOStats, int, error)

SysBlockDeviceStat returns stats for the block device read from /sys/block/<device>/stat. The number of stats read will be 15 if the discard stats are available (kernel 4.18+) and 11 if they are not available.

func (FS) SysBlockDeviceUnderlyingDevices added in v0.8.0 

func (fs FS) SysBlockDeviceUnderlyingDevices(device string) (UnderlyingDeviceInfo, error)

func (FS) SysBlockDevices 

func (fs FS) SysBlockDevices() ([]string, error)

SysBlockDevices lists the device names from /sys/block/<dev>.

type IOStats 

type IOStats struct {
	// ReadIOs is the number of reads completed successfully.
	ReadIOs uint64
	// ReadMerges is the number of reads merged.  Reads and writes
	// which are adjacent to each other may be merged for efficiency.
	ReadMerges uint64
	// ReadSectors is the total number of sectors read successfully.
	ReadSectors uint64
	// ReadTicks is the total number of milliseconds spent by all reads.
	ReadTicks uint64
	// WriteIOs is the total number of writes completed successfully.
	WriteIOs uint64
	// WriteMerges is the number of reads merged.
	WriteMerges uint64
	// WriteSectors is the total number of sectors written successfully.
	WriteSectors uint64
	// WriteTicks is the total number of milliseconds spent by all writes.
	WriteTicks uint64
	// IOsInProgress is number of I/Os currently in progress.
	IOsInProgress uint64
	// IOsTotalTicks is the number of milliseconds spent doing I/Os.
	// This field increases so long as IosInProgress is nonzero.
	IOsTotalTicks uint64
	// WeightedIOTicks is the weighted number of milliseconds spent doing I/Os.
	// This can also be used to estimate average queue wait time for requests.
	WeightedIOTicks uint64
	// DiscardIOs is the total number of discards completed successfully.
	DiscardIOs uint64
	// DiscardMerges is the number of discards merged.
	DiscardMerges uint64
	// DiscardSectors is the total number of sectors discarded successfully.
	DiscardSectors uint64
	// DiscardTicks is the total number of milliseconds spent by all discards.
	DiscardTicks uint64
	// FlushRequestsCompleted is the total number of flush request completed successfully.
	FlushRequestsCompleted uint64
	// TimeSpentFlushing is the total number of milliseconds spent flushing.
	TimeSpentFlushing uint64
}

IOStats models the iostats data described in the kernel documentation. - https://www.kernel.org/doc/Documentation/iostats.txt, - https://www.kernel.org/doc/Documentation/block/stat.txt - https://www.kernel.org/doc/Documentation/ABI/testing/procfs-diskstats

type Info 

type Info struct {
	MajorNumber uint32
	MinorNumber uint32
	DeviceName  string
}

Info contains identifying information for a block device such as a disk drive.

type UnderlyingDeviceInfo added in v0.8.0 

type UnderlyingDeviceInfo struct {
	// DeviceNames is the list of devices names
	DeviceNames []string
}

UnderlyingDevices models the list of devices that this device is built from.

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