Configuration

Default configuration values are defined in settings.py. The client uses user-specific configuration files, expected in ~/.cmclient. The server configuration is given as command line parameter for cm-server.py

Configuration values may contain Python expressions and the variables $(HOST) and $(USER) referring to hostname and username of the client respectively.

Client

• MASTER_HOST: hostname or IP of machine running the CacheManager server
• MASTER_PORT: TCP port number of the CacheManager server
• CACHE_DIR: directory on local hard disks used for caching
• MIN_FREE: minimum free space on cache disk (bytes). If this value is exceeded, the client tries to delete old files.
• MAX_USAGE: maximum disk space used for caches per user (percent of total space). If this value is exceeded, the client tries to delete old files.
• MIN_AGE: minimum age (in terms of atime) of a file to be deleted (seconds)
• SOCKET_TIMEOUT: timeout for the network connection to the master (seconds)
• STAT_TIMEOUT: time to wait for status operations on remote files (seconds)
• IGNORE_BUNDLE: ignore special meaning of bundle archives (.bundle) (boolean)

A template can be found in cmclient.config.

Server

• PORT: TCP port number used
• CONNECTION_QUEUE: queue size of the server socket
• MAX_COPY_SERVER: maximum number of parallel transfers from/to file servers
• MAX_COPY_NODE: maximum number of parallel transfers from/to compute nodes
• DB_FILE: database persistence file
• DB_SAVE_INTERVAL: interval between database writes (seconds)
• STAT_INTERVAL: interval between statistics writes (seconds)
• CLEANUP_INTERVAL: interval between database cleanups (seconds)
• SOCKET_TIMEOUT: timeout for client sockets (seconds)
• MAX_WAIT_COPY: maximum time a client may spend copying (seconds). If a client does not answer within this interval, the connection is assumed dead.
• CLIENT_WAIT: time a client has to wait if the MAX_COPY_SERVER is reached before next copy attempt (seconds)
• MAX_AGE: time after an unused record in the database is deleted (seconds)

A template can be found in cmserver.config.

Inter-Node Communication

The file system access across compute nodes is performed by default using SSH. If all compute nodes can access the local hard disks of each other using a network file system (e.g. NFS), you can define another ClientEnvironment class (see environment.py) and change the return value of clientEnvironment in settings.py.

Multi-Environment Setup

If the same client configuration is used in different environments, i.e. with different CacheManager servers, cache directories, or inter-node communication methods, you can define these environment specific values in a new ClientEnvironment class. See environment.py and settings.multienv.py for an example.