---
title: "Logical Volume Conditions"
description: "Check the capacity, health, and I/O statistics of the logical volume behind a simplyblock PersistentVolumeClaim with the metrics API and the CLI."
source: "https://docs.simplyblock.io/latest/kubernetes/operations/monitoring/lvol-conditions/"
---

# Logical Volume Conditions

Logical volumes are the core storage abstraction in simplyblock, representing high-performance, distributed NVMe
block devices backed by the cluster. On Kubernetes, every PersistentVolumeClaim of the simplyblock CSI driver is backed
by one logical volume. Its capacity is readable from the claim's own namespace through the metrics API, and its health
and I/O statistics are available through the CLI and the Grafana dashboards.

## Finding the Logical Volume of a Claim

The volume handle of a PersistentVolume has the form `<clusterUUID>:<poolUUID>:<volumeUUID>`, where the last part is
the UUID of the logical volume.

```bash title="Reading the volume handle of a claim"
kubectl get pv "$(kubectl get pvc my-pvc -n my-app -o jsonpath='{.spec.volumeName}')" \
  -o jsonpath='{.spec.csi.volumeHandle}'
```

## Accessing Logical Volume Capacity

The `LogicalVolumeMetrics` resource (short name `lvm`) is named after the PersistentVolumeClaim and lives in the
claim's namespace. It reports the volume handle, the PersistentVolume, the pool, and the capacity (`total`, `used`,
`free`, `provisioned`, and `utilizationPercent`).

```bash title="Reading the capacity of the volumes of a namespace"
kubectl -n my-app get lvm
```

```bash title="Reading the capacity of one volume"
kubectl -n my-app get lvm my-pvc -o yaml
```

Access follows Kubernetes RBAC, so a user bound to the built-in `view` role in the namespace can read the capacity of
the volumes there. See [Capacity Metrics API](index.md#capacity-metrics-api).

## Accessing Logical Volume Statistics

To access a logical volume's performance and I/O statistics, the `sbctl` command line tool can be used in the
`simplyblock-admin-control` pod (see [Using the CLI](cluster-health.md#using-the-cli)):

```bash title="Accessing the statistics of a logical volume"
sbctl volume get-io-stats <VOLUME_ID>
```

All details of the command are available in the [CLI reference](../../../reference/cli/index.md). The information is
also available through Grafana in the logical volume's dashboard.

## Accessing Logical Volume Health Information

To access a logical volume's health status, the `sbctl` command line tool can be used:

```bash title="Accessing the health status of a logical volume"
sbctl volume check <VOLUME_ID>
```

All details of the command are available in the [CLI reference](../../../reference/cli/index.md).