package main import ( "flag" "fmt" "os" ) var exampleConfigFile = []byte(` { "Client": { "APIHost": "zzzzz.arvadosapi.com:443", "AuthToken": "xyzzy", "Insecure": false }, "KeepServiceTypes": [ "disk" ], "RunPeriod": "600s", "CollectionBatchSize": 100000, "CollectionBuffers": 1000 }`) func usage() { fmt.Fprintf(os.Stderr, ` keep-balance rebalances a set of keepstore servers. It creates new copies of underreplicated blocks, deletes excess copies of overreplicated and unreferenced blocks, and moves blocks to better positions (according to the rendezvous hash algorithm) so clients find them faster. Usage: keep-balance -config path/to/config.json [options] Options: `) flag.PrintDefaults() fmt.Fprintf(os.Stderr, ` Example config file: %s Client.AuthToken must be recognized by Arvados as an admin token, and must be recognized by all Keep services as a "data manager key". Client.Insecure should be true if your Arvados API endpoint uses an unverifiable SSL/TLS certificate. Periodic scanning: By default, keep-balance operates periodically, i.e.: do a scan/balance operation, sleep, repeat. RunPeriod determines the interval between start times of successive scan/balance operations. If a scan/balance operation takes longer than RunPeriod, the next one will follow it immediately. If SIGUSR1 is received during an idle period between operations, the next operation will start immediately. One-time scanning: Use the -once flag to do a single operation and then exit. The exit code will be zero if the operation was successful. Committing: By default, keep-service computes and reports changes but does not implement them by sending pull and trash lists to the Keep services. Use the -commit-pull and -commit-trash flags to implement the computed changes. Tuning resource usage: CollectionBatchSize limits the number of collections retrieved per API transaction. If this is zero or omitted, page size is determined by the API server's own page size limits (see max_items_per_response and max_index_database_read configs). CollectionBuffers sets the size of an internal queue of collections. Higher values use more memory, and improve throughput by allowing keep-balance to fetch the next page of collections while the current page is still being processed. If this is zero or omitted, pages are processed serially. Limitations: keep-balance does not attempt to discover whether committed pull and trash requests ever get carried out -- only that they are accepted by the Keep services. If some services are full, new copies of underreplicated blocks might never get made, only repeatedly requested. `, exampleConfigFile) }