Controlling what Spectrum Scale file systems are mounted on a node

When a node starts running Spectrum Scale, the -A attribute of each Spectrum Scale file system is checked to determine whether or not the file system should be mounted. File systems configured with -A yes will automatically be mounted when the node starts Spectrum Scale. File systems configured with -A automount will be mounted when the file system is first used. File systems configured with -A no will not automatically be mounted.

The order in which file systems are mounted can be controlled by setting the --mount-priority setting on the file system. This is an integer, and file systems with a lesser mount priority are mounted before file systems with a greater mount priority.

All nodes end up with the same set of file systems mounted, and usually this is the desired behavior. But sometimes we would like certain file systems to only be mounted on some cluster nodes — or possibly we do not want a node to mount any file system at all. We can use “flag files” to prevent a node from mounting some file systems.

These flag files reside in the /var/mmfs/etc directory. The available flag files are:

  • ignoreStartupMount — do not mount any file systems automatically when starting. But the mmmount command may mount file systems, and file systems may be “internally mounted”.
  • ignoreStartupMount.fsdevice — do not mount the file system with device name fsdevice when starting. However, it may be mounted using mmmount, or internally mounted.
  • ignoreAnyMount — do not mount any file systems, even internal mounts or using mmmount.
  • ignoreAnyMount.fsdevice — do not mount the file system device name fsdevice, even internal mounts or using mmmount.
  • localMountOptions.fsdevice — Additional mount options for the file system with short name fsdevice to be applied to this node, e.g., ro to mount read only.

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