Percona ClusterSync for MongoDB startup configuration

When starting the pcsm process, you can use the following options:

• --port: The port on which the server will listen (default: 2242)
• --source: The MongoDB connection string for the source cluster
• --target: The MongoDB connection string for the target cluster
• --log-level: The log level (default: “info”)
• --log-json: Output log in JSON format with disabled color
• --no-color: Disable log ASCI color

Example:

$ pcsm \
    --source <source-mongodb-uri> \
    --target <target-mongodb-uri> \
    --port 2242 \
    --log-level debug \
    --log-json

Environment variables

Alternatively, you can define the following environment variables:

Variable	Description	Default
PCSM_SOURCE_URI	MongoDB connection string for the source cluster	-
PCSM_TARGET_URI	MongoDB connection string for the target cluster	-
PCSM_PORT	Server port number	2242
PCSM_CLONE_NUM_PARALLEL_COLLECTIONS	Number of collections cloned in parallel	2
PCSM_CLONE_NUM_READ_WORKERS	Number of read workers for cloning	NumCPU / 4
PCSM_CLONE_NUM_INSERT_WORKERS	Number of insert workers for cloning	NumCPU * 4
PCSM_MONGODB_CLI_OPERATION_TIMEOUT	Maximum time to wait before timing out MongoDB client operations such as insert, update, delete. If the timeout is reached, the operation will fail.	5m

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Last update: January 13, 2026
Created: January 13, 2026