Ceph is a highly scalable, open-source storage platform designed to provide excellent performance, reliability, and scalability. It is used to manage large amounts of data across distributed systems, offering block, object, and file storage in a unified system. Ceph's architecture is based on a cluster of nodes, which includes monitors (MONs), object storage daemons (OSDs), and metadata servers (MDSs). The monitors play a crucial role in maintaining the cluster map and ensuring the overall health of the cluster.
One common issue that can arise in a Ceph cluster is the 'MONITOR_DISK_FULL' error. This error indicates that one or more of the monitor nodes have run out of disk space, which can severely impact the cluster's ability to function correctly. When a monitor's disk is full, it may not be able to write new data or logs, leading to potential data inconsistencies and operational failures.
The 'MONITOR_DISK_FULL' issue occurs when the disk space allocated to a Ceph monitor is exhausted. This can happen due to various reasons, such as excessive logging, improper disk management, or unexpected data growth. When the disk is full, the monitor cannot perform its duties effectively, which can lead to cluster instability.
A full monitor disk can prevent the monitor from updating the cluster map, handling client requests, or maintaining cluster health. This can lead to degraded performance and potential data loss if not addressed promptly.
To resolve the 'MONITOR_DISK_FULL' issue, you need to take immediate action to free up space or expand the storage capacity of the affected monitor. Here are the steps you can follow:
First, identify which monitor is experiencing the disk full issue. You can use the following command to check the disk usage on each monitor node:
ceph df
This command will provide an overview of the disk usage across the cluster.
Once you have identified the affected monitor, you can free up disk space by removing unnecessary files or logs. Use the following command to list large files:
du -sh /* | sort -rh | head -n 10
Review the output and delete any unnecessary files to free up space.
If freeing up space is not sufficient, consider expanding the storage capacity of the monitor. This can be done by adding more disk space to the existing volume or attaching additional storage devices. Consult your cloud provider's documentation for specific instructions on expanding storage.
For more information on managing Ceph monitors and troubleshooting common issues, refer to the following resources:
By following these steps and utilizing the resources provided, you can effectively resolve the 'MONITOR_DISK_FULL' issue and ensure the smooth operation of your Ceph cluster.
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