Cluster workload

Each metadata server in a cluster, including the master metadata server, is assigned a workload. The workload is the amount of processing that is required to manage the locks, leases, and metadata on behalf of the clients when they request access to data that resides in a fileset in the global namespace. To the client, the fileset appears to be another directory, but to the metadata server, a fileset is an amount of workload. For example, a fileset that contains data that is frequently accessed by clients will have a higher workload than a fileset that stores archived data.

The workload is balanced among the metadata servers by assigning a set of filesets to each. SAN File System can automatically balance the workload for you by dynamically assigning filesets across all metadata servers.

You can also choose to control the workload manually by statically assigning the filesets to specific metadata servers. When assigning static filesets, consider the metadata-activity level of each fileset, and balance the filesets evenly across all metadata servers in the cluster. To ensure that each metadata server handles a share of the entire workload, assign at least one fileset to each metadata server. Creating additional filesets provides you with greater flexibility in assigning and reassigning filesets to achieve optimal results. You can statically assign a fileset to a metadata server or unassign a fileset at any time.

A spare metadata server is a metadata server that has no statically-assigned filesets but might be serving dynamic filesets if the filesets have been created in a mixed environment. You can reserve a spare metadata server for failover to take on the static workload of another metadata server that goes offline and preserve the workload balance.

During client setup, a client is given the address of one of the metadata servers for initial contact and metadata server cluster discovery. When the client issues a request to access data, it is automatically directed to the appropriate metadata server to obtain the metadata and locks required to access the data.

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Parent topic: Cluster

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