130 lines
5.8 KiB
Markdown
130 lines
5.8 KiB
Markdown
# DiskIO Input Plugin
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The diskio input plugin gathers metrics about disk traffic and timing.
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### Configuration:
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```toml
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# Read metrics about disk IO by device
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[[inputs.diskio]]
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## By default, telegraf will gather stats for all devices including
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## disk partitions.
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## Setting devices will restrict the stats to the specified devices.
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# devices = ["sda", "sdb"]
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## Uncomment the following line if you need disk serial numbers.
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# skip_serial_number = false
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#
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## On systems which support it, device metadata can be added in the form of
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## tags.
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## Currently only Linux is supported via udev properties. You can view
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## available properties for a device by running:
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## 'udevadm info -q property -n /dev/sda'
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# device_tags = ["ID_FS_TYPE", "ID_FS_USAGE"]
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#
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## Using the same metadata source as device_tags, you can also customize the
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## name of the device via templates.
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## The 'name_templates' parameter is a list of templates to try and apply to
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## the device. The template may contain variables in the form of '$PROPERTY' or
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## '${PROPERTY}'. The first template which does not contain any variables not
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## present for the device is used as the device name tag.
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## The typical use case is for LVM volumes, to get the VG/LV name instead of
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## the near-meaningless DM-0 name.
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# name_templates = ["$ID_FS_LABEL","$DM_VG_NAME/$DM_LV_NAME"]
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```
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#### Docker container
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To monitor the Docker engine host from within a container you will need to
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mount the host's filesystem into the container and set the `HOST_PROC`
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environment variable to the location of the `/proc` filesystem. Additionally,
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it is required to use privileged mode to provide access to `/dev`.
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If you are using the `device_tags` or `name_templates` options, you will need
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to bind mount `/run/udev` into the container.
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```
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docker run --privileged -v /:/hostfs:ro -v /run/udev:/run/udev:ro -e HOST_PROC=/hostfs/proc telegraf
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```
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### Metrics:
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- diskio
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- tags:
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- name (device name)
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- serial (device serial number)
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- fields:
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- reads (integer, counter)
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- writes (integer, counter)
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- read_bytes (integer, counter, bytes)
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- write_bytes (integer, counter, bytes)
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- read_time (integer, counter, milliseconds)
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- write_time (integer, counter, milliseconds)
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- io_time (integer, counter, milliseconds)
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- weighted_io_time (integer, counter, milliseconds)
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- iops_in_progress (integer, gauge)
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On linux these values correspond to the values in
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[`/proc/diskstats`](https://www.kernel.org/doc/Documentation/ABI/testing/procfs-diskstats)
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and
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[`/sys/block/<dev>/stat`](https://www.kernel.org/doc/Documentation/block/stat.txt).
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#### `reads` & `writes`:
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These values increment when an I/O request completes.
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#### `read_bytes` & `write_bytes`:
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These values count the number of bytes read from or written to this
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block device.
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#### `read_time` & `write_time`:
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These values count the number of milliseconds that I/O requests have
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waited on this block device. If there are multiple I/O requests waiting,
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these values will increase at a rate greater than 1000/second; for
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example, if 60 read requests wait for an average of 30 ms, the read_time
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field will increase by 60*30 = 1800.
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#### `io_time`:
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This value counts the number of milliseconds during which the device has
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had I/O requests queued.
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#### `weighted_io_time`:
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This value counts the number of milliseconds that I/O requests have waited
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on this block device. If there are multiple I/O requests waiting, this
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value will increase as the product of the number of milliseconds times the
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number of requests waiting (see `read_time` above for an example).
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#### `iops_in_progress`:
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This value counts the number of I/O requests that have been issued to
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the device driver but have not yet completed. It does not include I/O
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requests that are in the queue but not yet issued to the device driver.
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### Sample Queries:
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#### Calculate percent IO utilization per disk and host:
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```
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SELECT non_negative_derivative(last("io_time"),1ms) FROM "diskio" WHERE time > now() - 30m GROUP BY "host","name",time(60s)
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```
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#### Calculate average queue depth:
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`iops_in_progress` will give you an instantaneous value. This will give you the average between polling intervals.
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```
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SELECT non_negative_derivative(last("weighted_io_time",1ms)) from "diskio" WHERE time > now() - 30m GROUP BY "host","name",time(60s)
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```
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### Example Output:
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```
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diskio,name=sda weighted_io_time=8411917i,read_time=7446444i,write_time=971489i,io_time=866197i,write_bytes=5397686272i,iops_in_progress=0i,reads=2970519i,writes=361139i,read_bytes=119528903168i 1502467254359000000
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diskio,name=sda1 reads=2149i,read_bytes=10753536i,write_bytes=20697088i,write_time=346i,weighted_io_time=505i,writes=2110i,read_time=161i,io_time=208i,iops_in_progress=0i 1502467254359000000
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diskio,name=sda2 reads=2968279i,writes=359029i,write_bytes=5376989184i,iops_in_progress=0i,weighted_io_time=8411250i,read_bytes=119517334528i,read_time=7446249i,write_time=971143i,io_time=866010i 1502467254359000000
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diskio,name=sdb writes=99391856i,write_time=466700894i,io_time=630259874i,weighted_io_time=4245949844i,reads=2750773828i,read_bytes=80667939499008i,write_bytes=6329347096576i,read_time=3783042534i,iops_in_progress=2i 1502467254359000000
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diskio,name=centos/root read_time=7472461i,write_time=950014i,iops_in_progress=0i,weighted_io_time=8424447i,writes=298543i,read_bytes=119510105088i,io_time=837421i,reads=2971769i,write_bytes=5192795648i 1502467254359000000
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diskio,name=centos/var_log reads=1065i,writes=69711i,read_time=1083i,write_time=35376i,read_bytes=6828032i,write_bytes=184193536i,io_time=29699i,iops_in_progress=0i,weighted_io_time=36460i 1502467254359000000
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diskio,name=postgresql/pgsql write_time=478267417i,io_time=631098730i,iops_in_progress=2i,weighted_io_time=4263637564i,reads=2750777151i,writes=110044361i,read_bytes=80667939288064i,write_bytes=6329347096576i,read_time=3784499336i 1502467254359000000
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```
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