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## Overview

The free space available to a monitor’s store is critically low (<5% by default). You should increase the space available to the monitor(s). The monitor’s store can be found at `/var/lib/rook/<MON_NAME>/data` on the host.

Look for old, rotated versions of `.log` and `MANIFEST`. IMPORTANT: Don’t touch any `*.sst` files. Also check any other directories under `/var/lib/rook` and other directories on the same filesystem, often `/var/log` and `/var/tmp` are culprits.

## Steps for debugging

### Check node low on disk space

``````$ceph_cluster_ns=syn-rook-ceph-cluster$ ceph_mon_name=a (1)
$kubectl -n${ceph_cluster_ns} get deploy -lapp=rook-ceph-mon,mon=\${ceph_mon_name}  -ojson | jq '.items[].spec.template.spec.nodeSelector'
{
"kubernetes.io/hostname": "storage-XXXX" (2)
}``````
 1 The name of the monitor that’s alerting. 2 The node that the monitor is running on.

### Increase the size of the node’s disk

Increase the size of the node’s disk according to your cloud provider’s documentation.