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  <header>
    <copyright>
      <year>1996</year><year>2021</year>
      <holder>Ericsson AB. All Rights Reserved.</holder>
    </copyright>
    <legalnotice>
      Licensed under the Apache License, Version 2.0 (the "License");
      you may not use this file except in compliance with the License.
      You may obtain a copy of the License at
 
          http://www.apache.org/licenses/LICENSE-2.0

      Unless required by applicable law or agreed to in writing, software
      distributed under the License is distributed on an "AS IS" BASIS,
      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      See the License for the specific language governing permissions and
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    </legalnotice>

    <title>disksup</title>
    <prepared></prepared>
    <docno></docno>
    <date></date>
    <rev></rev>
  </header>
  <module since="">disksup</module>
  <modulesummary>A Disk Supervisor Process</modulesummary>
  <description>
    <p><c>disksup</c> is a process which supervises the available disk
      space in the system. It is part of the OS_Mon application, see
      <seeapp marker="os_mon_app">os_mon(6)</seeapp>. Available for Unix
      and Windows.</p>
    <p>Periodically checks the disks. For each disk or partition which
      uses more than a certain amount of the available space, the alarm
      <c>{{disk_almost_full, MountedOn}, []}</c> is set.</p>
    <taglist>
      <tag>On Unix</tag>
      <item>
        <p>All (locally) mounted disks are checked, including the swap
          disk if it is present.</p>
      </item>
      <tag>On WIN32</tag>
      <item>
        <p>All logical drives of type "FIXED_DISK" are checked.</p>
      </item>
    </taglist>
    <p>Alarms are reported to the SASL alarm handler, see
      <seeerl marker="sasl:alarm_handler">alarm_handler(3)</seeerl>.
      To set an alarm, <c>alarm_handler:set_alarm(Alarm)</c> is called
      where <c>Alarm</c> is the alarm specified above.</p>
    <p>The alarms are cleared automatically when the alarm cause is no
      longer valid.</p>
  </description>

  <section>
    <marker id="config"></marker>
    <title>Configuration</title>
    <p>The following configuration parameters can be used to change
      the default values for time interval and threshold:</p>
    <taglist>
      <tag><c>disk_space_check_interval = int()>0</c></tag>
      <item>
        <p>The time interval, in minutes, for the periodic disk space
          check. The default is 30 minutes.</p>
      </item>
      <tag><c>disk_almost_full_threshold = float()</c></tag>
      <item>
        <p>The threshold, as percentage of total disk space, for how
          much disk can be utilized before the <c>disk_almost_full</c>
          alarm is set. The default is 0.80 (80%).</p>
      </item>
      <tag><c>disksup_posix_only = bool()</c></tag>
      <item>
        <p>Specifies whether the <c>disksup</c> helper process should only
          use POSIX conformant commands (<c>true</c>) or not. The default is
          <c>false</c>. Setting this parameter to <c>true</c> can be
          necessary on embedded systems with stripped-down versions
          of Unix tools like <c>df</c>. The returned disk data and alarms
          can be different when using this option.</p>
        <p>The parameter is ignored on platforms that are known to not be
          POSIX compatible (Windows and SunOS).</p>
      </item>
    </taglist>
    <p>See <seefile marker="kernel:config">config(4)</seefile> for
      information about how to change the value of configuration
      parameters.</p>
  </section>
  <funcs>
    <func>
      <name since="">get_disk_data() -> [DiskData]</name>
      <fsummary>Get data for the disks in the system</fsummary>
      <type>
        <v>DiskData = {Id, KByte, Capacity}</v>
        <v>&nbsp;Id = string()</v>
        <v>&nbsp;KByte = int()</v>
        <v>&nbsp;Capacity = int()</v>
      </type>
      <desc>
        <p>Returns the result of the latest disk check. <c>Id</c> is a
          string that identifies the disk or partition. <c>KByte</c> is
          the total size of the disk or partition in kbytes.
          <c>Capacity</c> is the percentage of disk space used.</p>
        <p>The function is asynchronous in the sense that it does not
          invoke a disk check, but returns the latest available value.</p>
        <p>Returns <c>[{"none",0,0}]</c> if <c>disksup</c> is not
          available.</p>
      </desc>
    </func>
    <func>
      <name since="">get_check_interval() -> MS</name>
      <fsummary>Get time interval, in milliseconds, for the periodic disk space check</fsummary>
      <type>
        <v>MS = int()</v>
      </type>
      <desc>
        <p>Returns the time interval, in milliseconds, for the periodic
          disk space check.</p>
      </desc>
    </func>
    <func>
      <name since="">set_check_interval(Minutes) -> ok</name>
      <fsummary>Set time interval, in minutes, for the periodic disk space check</fsummary>
      <type>
        <v>Minutes = int()>=1</v>
      </type>
      <desc>
        <p>Changes the time interval, given in minutes, for the periodic
          disk space check.</p>
        <p>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 <seeerl marker="#config">Configuration</seeerl> above.</p>
      </desc>
    </func>
    <func>
      <name since="">get_almost_full_threshold() -> Percent</name>
      <fsummary>Get threshold, in percent, for disk space utilization</fsummary>
      <type>
        <v>Percent = int()</v>
      </type>
      <desc>
        <p>Returns the threshold, in percent, for disk space utilization.</p>
      </desc>
    </func>
    <func>
      <name since="">set_almost_full_threshold(Float) -> ok</name>
      <fsummary>Set threshold, as percentage represented by a float, for disk space utilization</fsummary>
      <type>
        <v>Float = float(), 0=&lt;Float=&lt;1</v>
      </type>
      <desc>
        <p>Changes the threshold, given as a float, for disk space
          utilization.</p>
        <p>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 <seeerl marker="#config">Configuration</seeerl> above.</p>
      </desc>
    </func>
  </funcs>

  <section>
    <title>See Also</title>
    <p><seeerl marker="sasl:alarm_handler">alarm_handler(3)</seeerl>,
      <seeapp marker="os_mon_app">os_mon(3)</seeapp></p>
  </section>
</erlref>

