The cassandra.yaml configuration file

(Default: Test Cluster) The name of the cluster. This setting prevents nodes in one logical cluster from joining another. All nodes in a cluster must have the same value.

(Default: localhost) The IP address or hostname that the database binds to for connecting this node to other nodes.

The interface that the database uses to connect to other nodes. Interfaces must correspond to a single address. IP aliasing is not supported.

The directory where the CDC log is stored. Default locations:

The directory where the commit log is stored. Default location: /var/lib/cassandra/commitlog

The directory location where table data is stored (in SSTables). The database distributes data evenly across the location, subject to the granularity of the configured compaction strategy. Default locations: /var/lib/cassandra/data.

The directory location where table key and row caches are stored. For all installations, the default location of the saved_caches directory is /var/lib/cassandra/saved_caches.

Default: auto. Disk access mode.

Default: stop. Policy for commit disk failures:

Default: auto, which is 1/256th of the heap or 10 MB, whichever is greater. Maximum size of the native protocol prepared statement cache.

Default: auto, which is 1/256th of the heap or 10 MB, whichever is greater. Maximum size of the Thrift prepared statement cache. Leave empty if you do not use Thrift.

Default: disabled. ^note The strategy for optimizing disk reads. Possible values: ssd or spinning.

Default: stop. Sets how the database responds to disk failure. Recommend settings: stop or best_effort. Valid values:

Default: DseSimpleSnitch. Set to a class that implements the IEndpointSnitch interface. The database uses the snitch to locate nodes and route requests.

Default: localhost. The listen address for client connections (Thrift RPC service and native transport). Valid values:

Default: eth1. ^note The listen address for client connections. Interface must correspond to a single address, IP aliasing is not supported. See rpc_address.

Default: false. Use IPv4 or IPv6 when interface is specified by name.

The addresses of hosts designated as contact points in the cluster. A joining node contacts one of the nodes in the -seeds list to learn the topology of the ring.

Default: false. User defined functions (UDFs) present a security risk, since they are executed on the server side. UDFs are executed in a sandbox to contain the execution of malicious code. They are disabled by default.

Default: false. Java UDFs are always enabled, if enable_user_defined_functions is true. Enable this option to use UDFs with language javascript or any custom JSR-223 provider. This option has no effect if enable_user_defined_functions is false.

Default: 16. Throttles compaction to the specified Mb/second across the instance. The faster the database inserts data, the faster the system must compact in order to keep the SSTable count down. The recommended value is 16 to 32 times the rate of write throughput (in Mb/second). Setting the value to 0 disables compaction throttling.

Default: 100. The database logs a warning when compacting partitions larger than the set value.

Default: 1/4 of heap size. ^note

Default: 1/4 of heap size. ^note

Default: 32. ^note Workloads with more data than can fit in memory encounter a bottleneck in fetching data from disk during reads. Setting concurrent_reads to (16 × number_of_drives) allows operations to queue low enough in the stack so that the OS and drives can reorder them. The default setting applies to both logical volume managed (LVM) and RAID drives.

Default: 32. ^note Writes in DSE are rarely I/O bound, so the ideal number of concurrent writes depends on the number of CPU cores on the node. The recommended value is 8 × number_of_cpu_cores.

Default: 32. ^note Counter writes read the current values before incrementing and writing them back. The recommended value is (16 × number_of_drives) .

Default: 32. Limit on the number of concurrent materialized view writes. Set this to the lesser of concurrent reads or concurrent writes, because there is a read involved in each materialized view write.

Default: false. Backs up data updated since the last snapshot was taken. When enabled, the database creates a hard link to each SSTable flushed or streamed locally in a backups subdirectory of the keyspace data. Removing these links is the operator’s responsibility.

Default: false. Enables or disables taking a snapshot before each compaction. A snapshot is useful to back up data when there is a data format change. Be careful using this option: the database does not clean up older snapshots automatically.

When enabled, every time the user drops a column/columns from a table, a snapshot is created on each node in the cluster before the change in schema is applied. Those snapshots have the same name on each node. For example: auto-snapshot_drop-column-columnname_20200515143511000. The name includes the name of the dropped column and the timestamp (UTC) when the column was dropped.

Default: 8. ^note Adjusts the sensitivity of the failure detector on an exponential scale. Generally this setting does not need adjusting.

Commit log synchronization method:

Default: 10000. Use with commitlog_sync: periodic. Controls how often the commit log is synchronized to disk. Periodic syncs are acknowledged immediately.

Default: disabled. Use with commitlog_sync:batch. The maximum length of time that queries may be batched together.

Disk usage threshold for commit logs before triggering the database flushing memtables to disk. If the total space used by all commit logs exceeds this threshold, the database flushes memtables to disk for the oldest commitlog segments to reclaim disk space by removing those log segments from the commit log. This flushing reduces the amount of data to replay on start-up, and prevents infrequently updated tables from keeping commitlog segments indefinitely.

Default: ½ of commitlog_segment_size_in_mb.

The compressor to use if commit log is compressed. To make changes, uncomment the commitlog_compression section and make changes to these options:

# commitlog_compression:
#   - class_name: LZ4Compressor
#     parameters:
#         -

Maximum number of permitted concurrent lightweight transactions (LWT).

Maximum number of lightweight transactions (LWT) in the queue before node reports OverloadedException for LWTs.

Enables change data capture (CDC) functionality on a per-node basis. This modifies the logic used for write path allocation rejection.

Default: 4096 and 1/8th of the total space of the drive where the cdc_raw_directory resides.)^note If space gets above this value, the database throws WriteTimeoutException on Mutations including tables with CDC enabled. A CDCCompactor (a consumer) is responsible for parsing the raw CDC logs and deleting them when parsing is completed.

Default: 250.^note When the cdc_raw limit is hit and the CDCCompactor is either running behind or experiencing backpressure, this interval is checked to see if any new space for cdc-tracked tables has been made available.

Disk usage threshold for commit logs before triggering the database to flush memtables to disk. If the total space used by all commit logs exceeds this threshold, the database flushes memtables to disk for the oldest commitlog segments to reclaim disk space by removing those log segments from the log. This flushing reduces the amount of data to replay on start-up, and prevents infrequently-updated tables from keeping commitlog segments indefinitely. If the commitlog_total_space_in_mb is small, the result is more flush activity on less-active tables.

Default: 200. The threshold for log messages at the INFO level. Adjust to minimize logging.

Defaults to the smaller of number of disks or number of cores, with a minimum of 2 and a maximum of 8. ^note The number of concurrent compaction processes allowed to run simultaneously on a node, not including validation compactions for anti-entropy repair. Simultaneous compactions help preserve read performance in a mixed read-write workload by limiting the number of small SSTables that accumulate during a single long-running compaction. If your data directories are backed by SSDs, increase this value to the number of cores. If compaction running too slowly or too fast, adjust compaction_throughput_mb_per_sec first.

Default: 50. The compaction process opens SSTables before they are completely written and uses them in place of the prior SSTables for any range previously written. This setting helps to smoothly transfer reads between the SSTables by reducing page cache churn and keeps hot rows hot.

Default: heap_buffers. The method the database uses to allocate and manage memtable memory.

Default: 1/(memtable_flush_writers + 1). ^note Ratio used for automatic memtable flush. The database adds memtable_heap_space_in_mb to memtable_offheap_space_in_mb and multiplies the total by memtable_cleanup_threshold to get a space amount in MB. When the total amount of memory used by all non-flushing memtables exceeds this amount, the database flushes the largest memtable to disk.

Default: Smaller of 1/4 heap or 512. Total memory to use for SSTable-reading buffers.

Default: disabled. ^note Indicates whether the database allocates on-heap or off-heap memory when the SSTable buffer pool is exhausted (when the buffer pool has exceeded the maximum memory file_cache_size_in_mb), beyond this amount, the database stops caching buffers, but allocates on request.

Default: Smaller of number of disks or number of cores with a minimum of 2 and a maximum of 8. ^note The number of memtable flush writer threads. These threads are blocked by disk I/O, and each one holds a memtable in memory while blocked. If your data directories are backed by SSDs, increase this setting to the number of cores.

Default: 64. Granularity of the index of rows within a partition. For huge rows, decrease this setting to improve seek time. If you use key cache, be careful not to overwhelm it by making this setting too large. If you’re unsure of the size of the rows, it’s best to use the default setting.

Default: 5% of the heap size [empty]. ^note Fixed memory pool size in MB for SSTable index summaries. If the memory usage of all index summaries exceeds this limit, any SSTables with low read rates shrink their index summaries to meet this limit. This is a best-effort process. In extreme conditions, the database may use more than this amount of memory.

Default: 60. How frequently index summaries should be re-sampled. Re-sampling is done periodically to redistribute memory from the fixed-size pool to SSTables proportional their recent read rates. To disable, set to -1. This setting leaves existing index summaries at their current sampling level.

Default: 200. ^note Throttle for the throughput of all outbound streaming file transfers on a node. The database does mostly sequential I/O when streaming data during bootstrap or repair. This can saturate the network connection and degrade client (RPC) performance.

Default: 200. ^note Throttle for all streaming file transfers between datacenters, and for network stream traffic as configured with stream_throughput_outbound_megabits_per_sec.

Default: 300. ^note Specifies for node to send keep-alive message at this interval to prevent reset connections during streaming. The stream session fails when a keep-alive message is not received for 2 keep-alive cycles.

Default: true. When set to true, causes fsync to force the operating system to flush the dirty buffers at the set interval trickle_fsync_interval_in_kb. Enable this parameter to prevent sudden dirty buffer flushing from impacting read latencies. Recommended for use with SSDs, but not with HDDs.

Default: 10240. The size of the fsync in kilobytes.

Default: true. This setting has been removed from default configuration. It causes new (non-seed) nodes migrate the right data to themselves automatically. When initializing a fresh cluster without data, add auto_bootstrap: false.

Default: 64. Log a warning message when any multiple-partition batch size exceeds this value.

Default: 640. Fails any batch whose size exceeds this setting. The default value is 10X the value of batch_size_warn_threshold_in_kb.

Default: 10. Causes the database to log a WARN message on any batches not of type LOGGED that span across more partitions than this limit. The default value is 10 partitions.

Default: false. Enable or disable change data capture (CDC) functionality on a per-node basis. This modifies the logic used for write path allocation rejection (standard: never reject. cdc: reject Mutation containing a CDC-enabled table if at space limit in cdc_raw_directory).

Default: listen_address. ^note The public IP address this node uses to broadcast to other nodes outside the network or across regions in multiple-region EC2 deployments. If this property is commented out, the node uses the same IP address or hostname as listen_address. A node does not need a separate broadcast_address in a single-node or single-datacenter installation, or in an EC2-based network that supports automatic switching between private and public communication. It is necessary to set a separate listen_address and broadcast_address on a node with multiple physical network interfaces or other topologies where not all nodes have access to other nodes by their private IP addresses. For specific configurations, see the instructions for listen_address.

Default: false. If this node uses multiple physical network interfaces, set a unique IP address for broadcast_address and set listen_on_broadcast_address to true. This enables the node to communicate on both interfaces.

Default: 1 (disabled). Set this property for single-node-per-token architecture, in which a node owns exactly one contiguous range in the ring space. Setting this property overrides num_tokens.

Default: 1 (disabled)

Default: org.apache.cassandra.dht.Murmur3Partitioner. Sets the class that distributes rows (by partition key) across all nodes in the cluster. Any IPartitioner may be used, including your own as long as it is in the class path. For new clusters use the default partitioner.

Default: 7000. The port for inter-node communication.

Default: 86400. TTL for different trace types used during logging of the query process.

Default: 604800. TTL for different trace types used during logging of the repair process.

Default: true. Enables or disables whether the database takes a snapshot of the data before truncating a keyspace or dropping a table. To prevent data loss, DataStax strongly advises using the default setting. If you set auto_snapshot to false, you lose data on truncation or drop.

Default: disabled. All keys are saved. ^note Number of keys from the key cache to save.

Default: 14400. (4 hours) Duration in seconds that keys are kept in cache. Caches are saved to saved_caches_directory. Saved caches greatly improve cold-start speeds and have relatively little effect on I/O.

Default: empty. A global cache setting for the maximum size of the key cache in memory (for all tables). If no value is set, the cache is set to the smaller of 5% of the available heap, or 100MB. To disable set to 0.

Default: 2. A threshold for the total size of all index entries for a partition that the database stores in the partition key cache. If the total size of all index entries for a partition exceeds this amount, the database stops putting entries for this partition into the partition key cache. This limitation prevents index entries from large partitions from taking up all the space in the partition key cache (which is controlled by key_cache_size_in_mb).

Default: disabled. ^note The classname of the row cache provider to use. Valid values: OHCProvider (fully off-heap) or SerializingCacheProvider (partially off-heap).

Default: disabled. All keys are saved. ^note Number of keys from the row cache to save.

Default: 0. To disable, set to 0. Maximum size of the row cache in memory. The row cache can save more time than key_cache_size_in_mb,, but it is space-intensive because it contains the entire row. Use the row cache only for hot rows or static rows. If you reduce the size, you may not get you hottest keys loaded on start up.

Default: 0. To disable, set to 0. The number of seconds that rows are kept in cache. Caches are saved to saved_caches_directory. This setting has limited use as described in row_cache_size_in_mb.

Default value: empty. ^note When no value is set, the database uses the smaller of minimum of 2.5% of Heap or 50 megabytes (MB). If your system performs counter deletes and relies on low gc_grace_seconds, you should disable the counter cache. To disable, set to 0.

Default: 7200. (2 hours) the amount of time after which the database saves the counter cache (keys only). The database saves caches to saved_caches_directory.

Default value: disabled. ^note Number of keys from the counter cache to save. When this property is disabled, the database saves all keys.

Default: 1000. The database issues a warning if a query scans more than this number of tombstones.

Default: 100000. The database aborts a query if it scans more than this number of tombstones.

Number of milliseconds that the coordinator waits for aggregated read operations to complete. For example, SELECT COUNT(*), MIN(x). Default: 120000.

Default: 1000. The number of milliseconds during which the coordinator continues to retry a CAS (compare and set) operation that contends with other proposals for the same row. If the coordinator cannot complete the operation within this timespan, it aborts the operation.

Default: 5000. The number of milliseconds that the coordinator waits for counter writes to complete before timing it out.

Default: 10000. The number of milliseconds that the coordinator waits for sequential or index scans to complete before timing it out.

Default: 5000. The number of milliseconds that the coordinator waits for read operations to complete before timing it out.

Default: 10000. The default timeout value for other miscellaneous operations.

Default: 500. How long before a node logs slow queries. Select queries that exceed this value generate an aggregated log message to identify slow queries. To disable, set to 0.

Default: 60000. The number of milliseconds that the coordinator waits for a truncate (the removal of all data from a table) to complete before timing it out. The long default value allows the database to take a snapshot before removing the data. If auto_snapshot is disabled (not recommended), you can reduce this time.

Default: 2000. The number of milliseconds that the coordinator waits for a write operations to complete before timing it out for requests with at least one node in the local datacenter.

Default: 0. Increases the cross-datacenter timeout (write_request_timeout_in_ms + cross_dc_rtt_in_ms) for requests that only involve nodes in a remote datacenter. This setting is intended to reduce hint pressure.

Default: false. Enables or disables operation timeout information exchange between nodes (to accurately measure request timeouts). If this property is disabled, the replica assumes any requests are forwarded to it instantly by the coordinator. During overload conditions this means extra time is required for processing already-timed-out requests..

Default: empty. ^note The sending socket buffer size in bytes for inter-node calls.

Default: empty. ^note The receiving socket buffer size in bytes for inter-node calls.

Default: dc. Controls whether traffic between nodes is compressed. Valid values:

Default: false. Enable this property or disable tcp_nodelay for inter-datacenter communication. If this property is disabled, the network sends larger, but fewer, network packets. This reduces overhead from the TCP protocol itself. However, disabling inter_dc_tcp_nodelay may increase latency by blocking cross datacenter responses.

Default: true. Enables or disables the native transport server. This server uses the same address as the rpc_address, but the port it uses is different from rpc_port. See native_transport_port.

Default: 9042. The port where the CQL native transport listens for clients.

Default: 128. ^note The maximum number of thread handling requests. Similar to rpc_max_threads, but this property differs as follows:

Default: 256. The maximum allowed size of a frame. Frame (requests) larger than this are rejected as invalid.

Default: -1. The maximum number of concurrent client connections. The default value of -1 means unlimited.

Default: -1. The maximum number of concurrent client connections per source IP address. The default value of -1 means unlimited.

Default: empty. ^note The RPC address for broadcast to drivers and other nodes. This cannot be set to 0.0.0.0. If left blank, the database uses the rpc_address or rpc_interface. If rpc_address or rpc_interface is set to 0.0.0.0, this property must be set.

Default: 9160. Thrift port for client connections.

Default: true. Enables or disables the Thrift RPC server.

Default: true. Enables or disables keepalive on client connections (RPC or native).

Default: unlimited. ^note Regardless of your choice of RPC server (rpc_server_type), rpc_max_threads dictates the maximum number of concurrent requests in the RPC thread pool. If you are using the parameter sync (see rpc_server_type) it also dictates the number of clients that can be connected. A high number of client connections could cause excessive memory usage for the thread stack. Connection pooling on the client side is highly recommended. Setting a rpc_max_threads acts as a safeguard against misbehaving clients. If the number of threads reaches the maximum, the database blocks additional connections until a client disconnects.

Default: unlimited. ^note The minimum thread pool size for remote procedure calls.

Default: empty. ^note The receiving socket buffer size for remote procedure calls.

Default: empty. ^note The sending socket buffer size in bytes for remote procedure calls.

Default: sync. The database provides three options for the RPC server. sync and hsha performance is about the same, but hsha uses less memory.

Default: 1000. Any GC pause longer than this interval is logged at the WARN level. (By default, the database logs any GC pause greater than 200 ms at the INFO level.)

Default: DISABLED. Supported strategies are: FIXED, MOVINGAVERAGE, TIMEHORIZON, and DISABLED. Suitable for VMs, but not noticeably performant in other environments. The OutboundTcpConnection (otc) strategy to:

Default: disabled. ^note How many microseconds to wait for coalescing. For fixed strategy, the amount of time after the first message is received before it is sent with any accompanying messages. For moving average, this is the maximum wait time and the interval that messages must arrive on average to enable coalescing.

Default: disabled. ^note The threshold for the number of messages. Do not coalesce messages when this value is exceeded. Should be more than 2 and less than 128.

The percentage of time that gossip messages are sent to a seed node during each round of gossip. Decreases the time to propagate gossip changes across the cluster. Default: 1.0 (100%)

Default: false. Enable for the coordinator to apply the specified back pressure strategy to each mutation that is sent to replicas.

The directory in which hints are stored. If not set, the directory is $CASSANDRA_HOME/data/hints.

Enables or disables hinted handoff. A hint indicates that the write needs to be replayed to an unavailable node. The database writes the hint to a hints file on the coordinator node.

A blacklist of datacenters that do not perform hinted handoffs. To disable hinted handoff on a certain datacenter, add its name to this list.

Default: 1024. Maximum amount of traffic per delivery thread in kilobytes per second. This rate reduces proportionally to the number of nodes in the cluster. For example, if there are two nodes in the cluster, each delivery thread uses the maximum rate. If there are three, each node throttles to half of the maximum, since the two nodes are expected to deliver hints simultaneously.

Default: 10800000. (3 hours) Maximum amount of time during which the database generates hints for an unresponsive node. After this interval, the database does not generate any new hints for the node until it is back up and responsive. If the node goes down again, the database starts a new interval. This setting can prevent a sudden demand for resources when a node is brought back online and the rest of the cluster attempts to replay a large volume of hinted writes.

Default: 2. Number of threads the database uses to deliver hints. In multiple datacenter deployments, consider increasing this number because cross datacenter handoff is generally slower.

Default: 128. The maximum size for a single hints file, in megabytes.

Default: LZ4Compressor. The compressor for hint files. Supported compressors: LZ, Snappy, and Deflate. If you do not specify a compressor, the database does not compress hints files.

(Default: 1024 kilobytes per second) Total maximum throttle for replaying failed logged batches. Throttling is reduced proportionally to the number of nodes in the cluster.

Default: org.apache.cassandra.scheduler.NoScheduler. The scheduler to handle incoming client requests according to a defined policy. This scheduler is useful for throttling client requests in single clusters containing multiple keyspaces. This parameter is specifically for requests from the client and does not affect inter-node communication. Valid values:

Default: keyspace. ^note The scope of the scheduler’s activity. Currently the only valid value is keyspace.

Default: NoScheduler. A list of properties that define configuration options for request_scheduler.

Default: 15. Frame size (maximum field length) for Thrift. The frame is the row or part of the row that the application is inserting.

Default: com.datastax.bdp.cassandra.auth.DseAuthenticator. The authentication backend. The only supported authenticator is DseAuthenticator for external authentication with multiple authentication schemes such as Kerberos, LDAP, and internal authentication. Authenticators other than DseAuthenticator are deprecated and not supported. Some security features might not work correctly if other authenticators are used. See authentication_options in dse.yaml.

Default: enabled. ^note Internode authentication backend. It implements org.apache.cassandra.auth.AllowAllInternodeAuthenticator to allows or disallow connections from peer nodes.

Default: com.datastax.bdp.cassandra.auth.DseAuthorizer. The authorization backend. Authorizers other than DseAuthorizer are not supported. DseAuthorizer supports enhanced permission management of DSE-specific resources. Authorizers other than DseAuthorizer are deprecated and not supported. Some security features might not work correctly if other authorizers are used. See Authorization options in dse.yaml.

Default: com.datastax.bdp.cassandra.auth.DseRoleManager. The DSE Role Manager supports LDAP roles and internal roles supported by the CassandraRoleManager. Role options are stored in the dse_security keyspace. When using the DSE Role Manager, increase the replication factor of the dse_security keyspace. Role managers other than DseRoleManager are deprecated and not supported. Some security features might not work correctly if other role managers are used.

Default: 2000. Validity period for roles cache; set to 0 to disable. Determines how long to cache the list of roles assigned to the user; users may have several roles, either through direct assignment or inheritance (a role that has been granted to another role). Adjust this setting based on the complexity of your role hierarchy, tolerance for role changes, the number of nodes in your environment, and activity level of the cluster.

Default: 2000. Enable to refresh interval for roles cache. Defaults to the same value as roles_validity_in_ms. After this interval, cache entries become eligible for refresh. On next access, the database schedules an async reload, and returns the old value until the reload completes. If roles_validity_in_ms is non-zero, then this must be also.

Default: 2000. How many milliseconds credentials in the cache remain valid. This cache is tightly coupled to the provided PasswordAuthenticator implementation of IAuthenticator. If another IAuthenticator implementation is configured, the database does not use this cache, and these settings have no effect.

Default: same value as credentials_validity_in_ms. After this interval, cache entries become eligible for refresh. The next time the cache is accessed, the system schedules an asynchronous reload of the cache. Until this cache reload is complete, the cache returns the old values.

Default: 2000. Fetching permissions can be resource intensive. Define how many milliseconds permissions in cache remain valid to manage performance impact of permissions queries. Set the cache validity period to your security tolerances. The cache is used for the standard authentication and the row-level access control (RLAC) cache. The cache is quite effective at small durations.

Default: same value as permissions_validity_in_ms. Sets refresh interval for the standard authentication cache and the row-level access control (RLAC) cache. After this interval, cache entries become eligible for refresh. On next access, the database schedules an async reload and returns the old value until the reload completes. If permissions_validity_in_ms is nonzero, roles_update_interval_in_ms must also be non-zero.

Default: 1000. The maximum number of entries that are held by the standard authentication cache and row-level access control (RLAC) cache. With the default value of 1000, the RLAC permissions cache can have up to 1000 entries in it, and the standard authentication cache can have up to 1000 entries. This single option applies to both caches. To size the permissions cache for use with Setting row-level permissions, use this formula:

numRlacUsers * numRlacTables + 100

Configure inter-node encryption. If enabled, you must also generate keys and provide the appropriate key and truststore locations and passwords. No custom encryption options are supported. Available options:

Enables or disables client-to-node encryption. You must also generate keys and provide the appropriate key and truststore locations and passwords. There are no custom encryption options currently enabled for DSE. Available options:

DSE only supports this option for backwards compatibility. When using DSE, configure data encryption options in the dse.yaml; see Transparent data encryption.

Default: 7001. The SSL port for encrypted communication. Unused unless enabled in encryption_options.

Default: 9142. If client encryption is enabled and native_transport_port_ssl is disabled, the native_transport_port (default: 9042) encrypts all traffic. To use both unencrypted and encrypted traffic, enable native_transport_port_ssl.

Pushes pages continuously to the client when requested by the client, parameters control: