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Chunkservers' Disk Preparation

Disk Mountpoint Naming Scheme

In a MooseFS cluster, proper management of storage devices is critical for ensuring smooth operation, easy maintenance, and rapid troubleshooting. One often overlooked but highly important best practice is adopting a consistent and meaningful naming scheme for disk mountpoints on Chunkservers.

A well-organized naming convention allows administrators to quickly identify faulty disks, locate affected hardware, and replace or repair components with minimal disruption. Without clear naming, diagnosing issues like disk failures, performance bottlenecks, or capacity planning becomes significantly more difficult.

Why a Consistent Naming Scheme Matters​

  • Faster Troubleshooting: When a Chunkserver reports errors related to a specific mountpoint, a clear name lets you immediately know which physical disk is affected.

  • Simplified Hardware Maintenance: Consistent names reduce the risk of replacing or removing the wrong drive.

  • Improved Monitoring and Alerting: Tools like Prometheus, Zabbix, or MooseFS monitoring tools can more clearly report disk-specific problems when mountpoints are logically named.

  • Better Documentation and Scaling: As your cluster grows, a consistent system helps new team members or external technicians understand the layout without confusion.

There is no single "correct" way to name mountpoints, but here are some effective and widely used strategies:

1. Use Disk Location or Slot Numbers​

If your servers have labeled drive bays, name mountpoints based on physical location.

Example:

/mnt/disk01
/mnt/disk02
/mnt/disk03
...

Where disk01 corresponds to Bay 1, disk02 to Bay 2, etc.

This allows quick physical identification when a disk fails.

2. Include Server or Host Information​

For larger deployments, you may want to prefix mountpoints with the server identifier, especially if managing disks remotely.

Example on server chunkserver01:

/mnt/chunkserver01-disk01
/mnt/chunkserver01-disk02

This helps when aggregating logs and alerts across many servers.

3. Include Disk Serial Numbers (Advanced)​

Some setups incorporate a shortened version of the disk’s serial number into the mountpoint name.

Example:

/mnt/sn-2FG34JK0
/mnt/sn-9FD83LM1

This provides absolute certainty about which disk the mountpoint corresponds to. However, it’s more complicated to set up and maintain.

4. Grouping by Disk Type or Size​

If your Chunkservers have disks of different sizes or types (e.g., SSDs and HDDs), you can reflect that in the naming:

Example:

/mnt/ssd01
/mnt/ssd02
/mnt/hdd01
/mnt/hdd02

This is especially useful for mixed-storage environments to help optimize performance.

Using a Local File System​

For disks dedicated to chunk storage, it is strongly recommended to format each disk with a local file system.

Prefer simple, stable file systems like ext4 or xfs that are optimized for direct disk access without additional redundancy layers. Avoid using network file systems (like NFS or iSCSI mounts) for Chunkserver storage, as these introduce extra latency and potential points of failure.

Each disk should be formatted, mounted individually, and listed explicitly in mfshdd.cfg. This ensures that MooseFS can properly manage disk space, monitor device health, and perform self-healing or rebalancing operations efficiently.

Key points:

  • One partition per disk is recommended.

  • No RAID is needed for disks storing MooseFS chunks (redundancy is handled at the file system level by MooseFS).

  • Mount each disk separately to a clearly named mountpoint.

Best Practices​

  • Keep names short but descriptive.

  • Document your naming convention and apply it consistently across the entire cluster.

  • Label physical disks or drive trays if possible to match your mountpoints.

  • Avoid relying only on device names like /dev/sda, /dev/sdb, etc., because these can change after reboots or hardware changes.

Summary​

By adopting a thoughtful, consistent disk naming scheme and using simple, local file systems, you greatly simplify operations, speed up hardware replacements, and reduce downtime during maintenance. These practices contribute to a more stable, efficient, and manageable MooseFS cluster, especially as your environment grows.