---
name: "pmdalio"
section: "1"
platform: "linux"
package: "pcp"
version: "7.2.2-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/pmdalio"
---

# pmdalio(1)

Linux LIO subsystem PMDA

## NAME

**pmdalio** - Linux LIO subsystem PMDA

## DESCRIPTION

**pmdalio** is a Performance Metrics Domain Agent (PMDA) which exports metric values about the Linux I/O target subsystem, which provides for protocols like iSCSI, FCP, FCoE. These allow storage available on one host to be exported and consumed by other hosts using industry standard protocols.

This PMDA exports summary metrics which are performance value aggregations and configuration per LIO target instance. Additionally, it provides per LUN performance metrics including IOPS, and READ and WRITE throughput.

The LIO configuration is maintained within the kernel's **configfs** virtual filesystem. The *python-rtslib* module provides an interface to **configfs**, allowing tools like **pmdalio** to interact with the settings and metadata held in **configfs**.

## INSTALLATION

Install the lio PMDA by using the Install script as root:

```
# cd $PCP_PMDAS_DIR/lio
# ./Install
```

To uninstall, do the following as root:

```
# cd $PCP_PMDAS_DIR/lio
# ./Remove
```

**pmdalio** is launched by [*pmcd*(1)](/pmcd/1.md) and should never be executed directly. The Install and Remove scripts notify [*pmcd*(1)](/pmcd/1.md) when the agent is installed or removed.

## FILES

- **$PCP\_PMDAS\_DIR/lio/Install**

  installation script for the **pmdalio** agent

- **$PCP\_PMDAS\_DIR/lio/Remove**

  undo installation script for the **pmdalio** agent

- **$PCP\_LOG\_DIR/pmcd/lio.log**

  default log file for error messages from **pmdalio**

## PCP ENVIRONMENT

Environment variables with the prefix **PCP\_** are used to parameterize the file and directory names used by **PCP**. On each installation, the file **/etc/pcp.conf** contains the local values for these variables. The **$PCP\_CONF** variable may be used to specify an alternative configuration file, as described in [*pcp.conf*(5)](/pcp.conf/5.md).

## SEE ALSO

[**PCPIntro**(1)](/PCPIntro/1.md), [**pmcd**(1)](/pmcd/1.md), [**pminfo**(1)](/pminfo/1.md) and [**pmpython**(1)](/pmpython/1.md).