Disk Alerts
Setup Disk Usage Alerts
Each service instance node comes with the a9s Parachute component. This
component monitors ephemeral and persistent disk usage. If one of these
disk usages reaches the default configured threshold of 80%
, the a9s
Parachute stops all processes on that node. Once the processes gets stopped,
a9s Parachute logs the following messages to its log directory:
Limit reached for: persistent disk
or
Limit reached for: ephemeral disk
How to restart stopped instances
To restart a stopped instance, the user can use the cf update-service
command
to set the max_disk_threshold
custom parameter. All values between 0
and
100
are allowed. Setting max_disk_threshold
to 0
disables disk usage alert.
Updating the instance does two things, at first the limit is set to the new
value and the instance will be restarted.
To set the value to 90%
do the following:
$ cf update-service <SERVICE_NAME> -c '{"max_disk_threshold": 90}'
The update will take some minutes until the service is restarted.
IMPORTANT: This is only a temporary solution. The nodes will be stopped when the threshold is reached again. For a long term solution the service instance must be updated to a bigger plan.
Set the Disk Threshold Service Wide
You can configure the max_disk_threshold
not only for a service instance.
You can configure it for every service plan.
To do so, you will need to extend the default_placeholder_values
in the
service configuration.
Note:
- If you want to configure the
max_disk_threshold
only for one specific plan (for examplemariadb-single-small
), you will need to adjust only this specific plan. - If you want to configure the
max_disk_threshold
for the complete data service offering, you will need to adjust every service plan in the configuration file.
Important
If you specify the max_disk_threshold
on the service plan level, you are no
longer able to overwrite it with cf update-service
.
Example
You want to configure a max_disk_threshold
of the
postgresql-single-small
service plan, to stop all processes on that node, when the disk usage exceeds
90%
(the default value is 80%
).
You need to adjust the service configuration like this:
postgresql-single-small:
[...]
default_placeholder_values:
[...]
max_disk_threshold: 90
migration_paths:
[...]