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glances/docs/aoa/diskio.rst
2026-05-04 14:59:20 +02:00

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.. _disk:
Disk I/O
========
.. image:: ../_static/diskio.png
Glances displays the disk I/O throughput, count and mean latency:
- bytes per second (default behavior / Bytes/s, KBytes/s, MBytes/s, etc)
- requests per second (using --diskio-iops option or *B* hotkey)
- mean latency (using --diskio-latency option or *L* hotkey)
It's also possible to define:
- a list of disk to show (white list)
- a list of disks to hide
- aliases for disk name (use \ to espace special characters)
under the ``[diskio]`` section in the configuration file.
For example, if you want to hide the loopback disks (loop0, loop1, ...)
and the specific ``sda5`` partition:
.. code-block:: ini
[diskio]
hide=sda5,loop.*
or another example:
.. code-block:: ini
[diskio]
show=sda.*
Filtering is based on regular expression. Please be sure that your regular
expression works as expected. You can use an online tool like `regex101`_ in
order to test your regular expression.
.. note::
When a disk has an ``alias`` defined, the ``hide`` and ``show`` patterns
are evaluated against **both** the original device name and its alias,
and the disk is hidden (or shown) if **either** matches. This means a
"negative-lookahead" allow-list pattern such as
``hide=^(?!(?:nvme[0-9]+n[0-9]+$|sd[a-z]+$)).*`` will inadvertently match
aliases that do not follow the device naming scheme (e.g. ``my_data_disk``)
and therefore hide every aliased disk. Prefer ``show=`` for allow-list
semantics, or write explicit ``hide=`` patterns that target the names you
actually want to exclude.
It is also possible to define thesholds for latency and bytes read and write per second:
.. code-block:: ini
[diskio]
# Alias for sda1 and sdb1
#alias=sda1:SystemDisk,sdb1:DataDisk
# Default latency thresholds (in ms) (rx = read / tx = write)
rx_latency_careful=10
rx_latency_warning=20
rx_latency_critical=50
tx_latency_careful=10
tx_latency_warning=20
tx_latency_critical=50
# Set thresholds (in bytes per second) for a given disk name (rx = read / tx = write)
dm-0_rx_careful=4000000000
dm-0_rx_warning=5000000000
dm-0_rx_critical=6000000000
dm-0_rx_log=True
dm-0_tx_careful=700000000
dm-0_tx_warning=900000000
dm-0_tx_critical=1000000000
dm-0_tx_log=True
You also can automatically hide disk with no read or write using the
``hide_zero`` configuration key. The optional ``hide_threshold_bytes`` option
can also be used to set a threshold higher than zero.
.. code-block:: ini
[diskio]
hide_zero=True
hide_threshold_bytes=0
.. _regex101: https://regex101.com/