# PMM Agent Not Monitoring PVC Mounted at /data/db in Percona Operator for MongoDB

**URL:** <https://forums.percona.com/t/pmm-agent-not-monitoring-pvc-mounted-at-data-db-in-percona-operator-for-mongodb/39330>\
**Category:** PMM 2.x\
**Created:** [September 10, 2025, 6:20pm UTC](https://forums.percona.com/t/pmm-agent-not-monitoring-pvc-mounted-at-data-db-in-percona-operator-for-mongodb/39330 "2025-09-10T18:20:15Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Stateros](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/stateros/32/2490_2.png) [@Stateros](https://forums.percona.com/u/Stateros)\
**Post date:** [September 10, 2025, 6:20pm UTC](https://forums.percona.com/t/pmm-agent-not-monitoring-pvc-mounted-at-data-db-in-percona-operator-for-mongodb/39330/1 "2025-09-10T18:20:15Z")

</div>

## Description:

Hi team,

I’m using the Percona Operator for MongoDB and have successfully enabled PMM integration across my clusters. All MongoDB metrics are working well. However, I’ve noticed that the PMM agent does **not monitor disk usage for the PVC mounted at `/data/db`** , which is the main data directory for `mongod`. Instead, it monitors the node’s root disk and other mounted paths like configuration volumes (e.g., SSL certs, keys), which are not helpful for tracking actual database storage usage.

Here is the list of devices that PMM cought:

```auto
"device": "/dev/nvme1n1p1",
"device": "/dev/nvme1n1p1",
"device": "/dev/nvme1n1p1",
"device": "/dev/root",
"device": "tmpfs",
"device": "tmpfs",
"device": "tmpfs",
"device": "/dev/nvme1n1p1",
"device": "/dev/nvme1n1p1",
"device": "/dev/nvme1n1p1",
"device": "/dev/root",
"device": "tmpfs",
"device": "tmpfs",
"device": "tmpfs",
"device": "/dev/nvme1n1p1",
"device": "/dev/nvme1n1p1",
"device": "/dev/nvme1n1p1",
"device": "/dev/root",
"device": "tmpfs",
"device": "tmpfs",
"device": "tmpfs",

```

What I need monitored is this volume:  
`/dev/nvme7n1 30G 13G 17G 43% /data/db`

## PMM config:

```auto
  pmm:
    enabled: true
    image: percona/pmm-client:2.43.1
    serverHost: pmm.domain.xyz
    mongodParams: --environment=sandbox --cluster=mycluster --replication-set=mycluster-rs0

```

## Version:

PMM server and clients: 2.43.1

Percona Operator for MongoDB: 1.20.1

Percona server for MongoDB: 7.0.18

## Questions:

1. Is there a supported way to configure PMM (via the Operator or otherwise) to monitor PVC disk usage?

2. How to monitor the k8s PVCs?

3. Are there any best practices or recommended workarounds for this scenario?

Any guidance or examples would be greatly appreciated!

##

---

<div class="post-metadata">

**Author:** ![Stateros](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/stateros/32/2490_2.png) [@Stateros](https://forums.percona.com/u/Stateros)\
**Post date:** [September 11, 2025, 4:26pm UTC](https://forums.percona.com/t/pmm-agent-not-monitoring-pvc-mounted-at-data-db-in-percona-operator-for-mongodb/39330/2 "2025-09-11T16:26:18Z")

</div>

After further debugging, I’ve confirmed that `node_exporter` can detect all devices and report general metrics like `node_disk_info`, but **critical metrics such as `node_filesystem_free_bytes` and `node_filesystem_used_bytes` are missing for the PVC mounted at `/data/db`**.

```bash
bash-5.1$ df -hT
Filesystem Type Size Used Avail Use% Mounted on
overlay overlay 100G 9.2G 91G 10% /
tmpfs tmpfs 64M 0 64M 0% /dev
/dev/root erofs 308M 308M 0 100% /usr/local/sbin/modprobe
tmpfs tmpfs 30G 12K 30G 1% /etc/mongodb-ssl
/dev/nvme0n1p1 xfs 100G 9.2G 91G 10% /etc/hosts
shm tmpfs 64M 0 64M 0% /dev/shm
tmpfs tmpfs 30G 12K 30G 1% /run/secrets/kubernetes.io/serviceaccount
tmpfs tmpfs 30G 4.0K 30G 1% /run/secrets/eks.amazonaws.com/serviceaccount

```

It appears the root cause is that the **PMM client sidecar container does not have access to the mounted device** at `/data/db`. I attempted to modify the `pmm.containerSecurityContext` to elevate permissions, but that didn’t resolve the issue.

```auto
containerSecurityContext:
  privileged: true

```

If anyone has encountered a similar issue or has ideas on how to grant PMM client access to PVC-mounted volumes for proper disk usage monitoring, I’d greatly appreciate any guidance or suggestions!