Erlang -- disksup

# disksup

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Module

disksup

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Module Summary

A Disk Supervisor Process

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Description

disksup is a process which supervises the available disk space in the system. It is part of the OS_Mon application, see os_mon(6). Available for Unix and Windows.

Periodically checks the disks. For each disk or partition which uses more than a certain amount of the available space, the alarm {{disk_almost_full, MountedOn}, []} is set.

On Unix

  All (locally) mounted disks are checked, including the swap disk if it is present.

On WIN32

  All logical drives of type "FIXED_DISK" are checked.

Alarms are reported to the SASL alarm handler, see alarm_handler(3). To set an alarm, alarm_handler:set_alarm(Alarm) is called where Alarm is the alarm specified above.

The alarms are cleared automatically when the alarm cause is no longer valid.

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Data Types

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time()

Supported units:

integer() >= 1

  The time interval in minutes.

{TimeUnit, Time}

  The time interval Time in a time unit specified by TimeUnit where TimeUnit is of the type erlang:time_unit() and Time is a positive integer. The time interval needs to be at least one millisecond long.

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Configuration

The following configuration parameters can be used to change the default values for time interval and threshold:

disk_space_check_interval = time()

  The time interval for the periodic disk space check. The default is 30 minutes.

disk_almost_full_threshold = float()

  The threshold, as percentage of total disk space, for how much disk can be utilized before the disk_almost_full alarm is set. The default is 0.80 (80%).

disksup_posix_only = bool()

  Specifies whether the disksup helper process should only use POSIX conformant commands (true) or not. The default is false. Setting this parameter to true can be necessary on embedded systems with stripped-down versions of Unix tools like df. The returned disk data and alarms can be different when using this option.

  The parameter is ignored on platforms that are known to not be POSIX compatible (Windows and SunOS).

See config(4) for information about how to change the value of configuration parameters.

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Exports

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get_disk_data() -> [DiskData]

### Types

DiskData = {Id, TotalKiB, Capacity}
Id = string()
TotalKiB = int()
Capacity = int()

Returns the result of the latest disk check. Id is a string that identifies the disk or partition. TotalKiB is the total size of the disk or partition in kibibytes. Capacity is the percentage of disk space used.

The function is asynchronous in the sense that it does not invoke a disk check, but returns the latest available value.

Returns [{"none",0,0}] if disksup is not available.

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get_disk_info() -> [DiskData]
OTP 26.0

### Types

DiskData = {Id, TotalKiB, AvailableKiB, Capacity}
Id = string()
TotalKiB = int()
AvailableKiB = int()
Capacity = int()

Immediately fetches total space, available space and capacity for local disks. Id is a string that identifies the disk or partition. TotalKiB is the total size of the disk or partition in kibibytes. AvailableKiB is the disk space used in kibibytes. Capacity is the percentage of disk space used.

Returns [{"none",0,0,0}] if disksup is not available.

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get_disk_info(Path) -> DiskData
OTP 26.0

### Types

DiskData = [{Id, TotalKiB, AvailableKiB, Capacity}]
Id = string()
TotalKiB = int()
AvailableKiB = int()
Capacity = int()

Immediately fetches total space, available space and capacity for a path. Id is a string that identifies the disk or partition. TotalKiB is the total size of the disk or partition in kibibytes. AvailableKiB is the disk space used in kibibytes. Capacity is the percentage of disk space used.

Returns [{Path,0,0,0}] if the Path is invalid or space can't be determined. Returns [{"none",0,0,0}] if disksup is not available.

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get_check_interval() -> MS

### Types

MS = int()

Returns the time interval, in milliseconds, for the periodic disk space check.

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set_check_interval(Time) -> ok

### Types

Time = time()

Changes the time interval for the periodic disk space check.

The change will take effect after the next disk space check and is non-persist. That is, in case of a process restart, this value is forgotten and the default value will be used. See Configuration above.

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get_almost_full_threshold() -> Percent

### Types

Percent = int()

Returns the threshold, in percent, for disk space utilization.

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set_almost_full_threshold(Float) -> ok

### Types

Float = float(), 0=<Float=<1

Changes the threshold, given as a float, for disk space utilization.

The change will take effect during the next disk space check and is non-persist. That is, in case of a process restart, this value is forgotten and the default value will be used. See Configuration above.

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See Also

alarm_handler(3), os_mon(3)