Monitoring DRBD (Distributed Replicated Storage System)
After you install the Instana host agent, the DRBD sensor is automatically installed. However, you must configure the DRBD sensor as outlined in this topic. Then, you can view the metrics that are related with DRBD in the Instana UI.
Supported information
Supported operating systems
The supported operating systems of DRBD sensor are consistent with host agents requirements, which can be checked in the Supported operating systems section of each host agent, such as Supported operating systems for Linux.
Supported DRBD versions and platforms
Instana supports metrics and configuration data from Distributed Replicated Storage System (DRBD) core version 9.1.7 and later. You need to install the DRBD reactor and configure the reactor information in the Instana configuration.yaml file. For more information about DRBD reactor installation, see DRBD reactor installation.
Notes:
- DRBD reactor must be installed as a prerequisite.
- Instana supports both remote monitoring and local monitoring for DRBD.
Configuring
You don't need to configure the configuration.yaml file to collect local monitoring data of DRBD because the Instana agent can automatically detect the DRBD reactor process and locate the port in the local environment.
To collect the remote monitoring data of DRBD, you need to configure the following fields in the agent configuration file <agent_install_dir>/etc/instana/configuration.yaml as follows:
The DRBD sensor instance connects to the DRBD reactor by using http request. Ensure that the configurations are correct.
See the following configurations in <agent_install_dir>/etc/instana/configuration.yaml:
# DRBD sensor
com.instana.plugin.drbd:
enabled: true # Default is true
poll_rate: 60 # Default is 60 seconds (Optional)
instances: # Multiple DRBD instances can be specified
DRBD_INSTANCE_HOST_1: # DRBD reactor Host or IP address
port: '<INSERT_PORT_HERE>' # DRBD reactor port
username: '<INSERT_USERNAME_HERE>' # User account to connect to DRBD reactor (Optional)
password: '<INSERT_PASSWORD_HERE>' # User password to connect to DRBD reactor (Optional)
availabilityZone: '<INSERT_AVAILABILITYZONE_HERE>' # Specify a zone for DRBD resources (Optional)
DRBD_INSTANCE_HOST_2: # DRBD reactor Host or IP address
port: '<INSERT_PORT_HERE>' # DRBD reactor port
username: '<INSERT_USERNAME_HERE>' # User account to connect to DRBD reactor (Optional)
password: '<INSERT_PASSWORD_HERE>' # User password to connect to DRBD reactor (Optional)
availabilityZone: '<INSERT_AVAILABILITYZONE_HERE>' # Specify a zone for DRBD resources (Optional)
Viewing metrics
To view the metrics, select Infrastructure in the sidebar of the Instana console, and locate DRBD Zone.
To view the metrics, complete the following steps:
- In the sidebar of the Instana UI, select Infrastructure.
- Click a specific monitored host.
Then, you can find the monitored DRBD resources if your configuration is correct.
DRBD Information
Configuration data
- DRBD Host
- DRBD reactor Kmod Version
- DRBD reactor Utils Version
Performance metrics
| DRBD information metric | Description |
|---|---|
| Resources Number | Total number of resources. |
| Suspended Resources Count | Count of resources that are suspended. |
Resource metrics
Configuration data
- Resource Name
- Resource Role
Performance metrics
| Resource metric | Description |
|---|---|
| Resource Suspended | Whether the resource is suspended. The value of 0 = No and 1 = Yes. |
| Resource May Promote | Whether the resource might be promoted to Primary. The value of 0 = No and 1 = Yes. |
| Resource Force IO Failures | Whether the resource is configured, which might be temporary, to force I/O failures (for example, during secondary --force). The value of 0 = No and 1 = Yes. |
| Resource Promotion Score | The promotion score for the resource. A higher score is better. |
| Resource Role | The DRBD role of the resource. |
Device Metrics
Configuration data
- Device Name
- Resource Name
- Volume
- Minor
- Device State
Performance metrics
| Device metric | Description |
|---|---|
| Device State | The state of the DRBD device. |
| Device Unintentional Diskless | Whether the device is unintentionally diskless. The value of 0 = No and 1 = Yes. |
| Device Size Bytes | The size of the device in bytes. |
| Device Read Bytes Total | Net data read from local hard disk. |
| device Written Bytes Total | Net data written on local disk. |
| Device Upper Pending | Total number of block I/O requests that were forwarded to DRBD, but not yet answered by DRBD. |
| Device Lower Pending | Total number of open requests to the local I/O subsystem that are issued by DRBD. |
| Device Al Suspended | Whether the resource is suspended. The value of 0 = No and 1 = Yes. |
| Device Al Writes Total | Total number of updates of the activity log area of the metadata. |
| Device Bm Writes Total | Total number of updates of the bitmap area of the metadata. |
| Device Quorum | Whether this device has DRBD quorum. The value of 0 = No and 1 = Yes. |
| Device Client | Whether the device is a client, which is intentionally diskless. The value of 0 = No and 1 = Yes. |
Connection Metrics
Configuration data
- Connection Unique Name
- Resource Name
- Connection Name
- Peer Node Id
- Connection State
Performance metrics
| Connection metric | Description |
|---|---|
| Connection State | The state of the DRBD connection. |
| Connection Rs In Flight Bytes | Total number of resync requests in flight. |
| Connection Ap In Flight Bytes | Total number of application requests in flight, which is not completed. |
| Connection Congested | Whether the buffer of the data connection that the TCP sends is more than 80% filled. The value of 0 = No and 1 = Yes. |
Peer Metrics
Configuration data
- Peer Device Name
- Resource Name
- Connection Name
- Peer Node Id
- Volume
Performance metrics
| Peer metric | Description |
|---|---|
| Peer Device Out Of Sync Bytes | Total number of bytes that are currently out-of-sync with the peer device according to the bitmap that DRBD consists of. |
Built-in events
You might see the following built-in events:
- DRBD Connection Congested
Verify whether the buffer that TCP sends of the data connection is more than 80% filled.
-
DRBD quorum status
Check whether the TCP sends buffer of the DRBD data connection is more than 80% filled.
-
DRBD resource is out of sync
Check whether this DRBD peer is out of sync.
Troubleshooting
Use the following troubleshooting entries to fix issues that are related to monitoring DRBD. An error message displays the stated issue type and summary of what went wrong on the DRBD dashboard in the Instana UI.
Invalid DRBD port
Monitoring issue type: Invalid DRBD reactor port
The monitoring issue indicates that the DRBD reactor port is incorrectly configured. For more information, see DRBD reactor configuration.