we are using a single node ( development environment) installed on the same machine of RWS ana below is the cassandra.yaml configuration:
Cassandra storage config YAML
NOTE:
full explanations of configuration directives
/NOTE
The name of the cluster. This is mainly used to prevent machines in
one logical cluster from joining another.
cluster_name: ‘Test Cluster’
This defines the number of tokens randomly assigned to this node on the ring
The more tokens, relative to other nodes, the larger the proportion of data
that this node will store. You probably want all nodes to have the same number
of tokens assuming they have equal hardware capability.
If you leave this unspecified, Cassandra will use the default of 1 token for legacy compatibility,
and will use the initial_token as described below.
Specifying initial_token will override this setting on the node’s initial start,
on subsequent starts, this setting will apply even if initial token is set.
If you already have a cluster with 1 token per node, and wish to migrate to
num_tokens: 256
initial_token allows you to specify tokens manually. While you can use # it with
vnodes (num_tokens > 1, above) – in which case you should provide a
comma-separated list – it’s primarily used when adding nodes # to legacy clusters
that do not have vnodes enabled.
initial_token:
May either be “true” or “false” to enable globally, or contain a list
of data centers to enable per-datacenter.
hinted_handoff_enabled: DC1,DC2
hinted_handoff_enabled: true
this defines the maximum amount of time a dead host will have hints
generated. After it has been dead this long, new hints for it will not be
created until it has been seen alive and gone down again.
max_hint_window_in_ms: 10800000 # 3 hours
Maximum throttle in KBs per second, per delivery thread. This will be
reduced proportionally to the number of nodes in the cluster. (If there
are two nodes in the cluster, each delivery thread will use the maximum
rate; if there are three, each will throttle to half of the maximum,
since we expect two nodes to be delivering hints simultaneously.)
hinted_handoff_throttle_in_kb: 1024
Number of threads with which to deliver hints;
Consider increasing this number when you have multi-dc deployments, since
cross-dc handoff tends to be slower
max_hints_delivery_threads: 2
Maximum throttle in KBs per second, total. This will be
reduced proportionally to the number of nodes in the cluster.
batchlog_replay_throttle_in_kb: 1024
Authentication backend, implementing IAuthenticator; used to identify users
Out of the box, Cassandra provides org.apache.cassandra.auth.{AllowAllAuthenticator,
PasswordAuthenticator}.
- AllowAllAuthenticator performs no checks - set it to disable authentication.
- PasswordAuthenticator relies on username/password pairs to authenticate
users. It keeps usernames and hashed passwords in system_auth.credentials table.
Please increase system_auth keyspace replication factor if you use this authenticator.
If using PasswordAuthenticator, CassandraRoleManager must also be used (see below)
authenticator: AllowAllAuthenticator
Authorization backend, implementing IAuthorizer; used to limit access/provide permissions
Out of the box, Cassandra provides org.apache.cassandra.auth.{AllowAllAuthorizer,
CassandraAuthorizer}.
- AllowAllAuthorizer allows any action to any user - set it to disable authorization.
- CassandraAuthorizer stores permissions in system_auth.permissions table. Please
increase system_auth keyspace replication factor if you use this authorizer.
authorizer: AllowAllAuthorizer
Part of the Authentication & Authorization backend, implementing IRoleManager; used
to maintain grants and memberships between roles.
Out of the box, Cassandra provides org.apache.cassandra.auth.CassandraRoleManager,
which stores role information in the system_auth keyspace. Most functions of the
IRoleManager require an authenticated login, so unless the configured IAuthenticator
actually implements authentication, most of this functionality will be unavailable.
- CassandraRoleManager stores role data in the system_auth keyspace. Please
increase system_auth keyspace replication factor if you use this role manager.
role_manager: CassandraRoleManager
Validity period for roles cache (fetching permissions can be an
expensive operation depending on the authorizer). Granted roles are cached for
authenticated sessions in AuthenticatedUser and after the period specified
here, become eligible for (async) reload.
Defaults to 2000, set to 0 to disable.
Will be disabled automatically for AllowAllAuthenticator.
roles_validity_in_ms: 2000
Refresh interval for roles cache (if enabled).
After this interval, cache entries become eligible for refresh. Upon next
access, an async reload is scheduled and the old value returned until it
completes. If roles_validity_in_ms is non-zero, then this must be
also.
Defaults to the same value as roles_validity_in_ms.
roles_update_interval_in_ms: 1000
Validity period for permissions cache (fetching permissions can be an
expensive operation depending on the authorizer, CassandraAuthorizer is
one example). Defaults to 2000, set to 0 to disable.
Will be disabled automatically for AllowAllAuthorizer.
permissions_validity_in_ms: 2000
Refresh interval for permissions cache (if enabled).
After this interval, cache entries become eligible for refresh. Upon next
access, an async reload is scheduled and the old value returned until it
completes. If permissions_validity_in_ms is non-zero, then this must be
also.
Defaults to the same value as permissions_validity_in_ms.
permissions_update_interval_in_ms: 1000
The partitioner is responsible for distributing groups of rows (by
partition key) across nodes in the cluster. You should leave this
alone for new clusters. The partitioner can NOT be changed without
reloading all data, so when upgrading you should set this to the
same partitioner you were already using.
Besides Murmur3Partitioner, partitioners included for backwards
compatibility include RandomPartitioner, ByteOrderedPartitioner, and
OrderPreservingPartitioner.
partitioner: org.apache.cassandra.dht.Murmur3Partitioner
Directories where Cassandra should store data on disk. Cassandra
will spread data evenly across them, subject to the granularity of
the configured compaction strategy.
If not set, the default directory is $CASSANDRA_HOME/data/data.
data_file_directories:
- /var/lib/cassandra/data
commit log. when running on magnetic HDD, this should be a
separate spindle than the data directories.
If not set, the default directory is $CASSANDRA_HOME/data/commitlog.
commitlog_directory: /var/lib/cassandra/commitlog
policy for data disk failures:
die: shut down gossip and client transports and kill the JVM for any fs errors or
single-sstable errors, so the node can be replaced.
stop_paranoid: shut down gossip and client transports even for single-sstable errors,
kill the JVM for errors during startup.
stop: shut down gossip and client transports, leaving the node effectively dead, but
can still be inspected via JMX, kill the JVM for errors during startup.
best_effort: stop using the failed disk and respond to requests based on
remaining available sstables. This means you WILL see obsolete
data at CL.ONE!
ignore: ignore fatal errors and let requests fail, as in pre-1.2 Cassandra
disk_failure_policy: stop
policy for commit disk failures:
die: shut down gossip and Thrift and kill the JVM, so the node can be replaced.
stop: shut down gossip and Thrift, leaving the node effectively dead, but
can still be inspected via JMX.
stop_commit: shutdown the commit log, letting writes collect but
continuing to service reads, as in pre-2.0.5 Cassandra
ignore: ignore fatal errors and let the batches fail
commit_failure_policy: stop
Maximum size of the key cache in memory.
Each key cache hit saves 1 seek and each row cache hit saves 2 seeks at the
minimum, sometimes more. The key cache is fairly tiny for the amount of
time it saves, so it’s worthwhile to use it at large numbers.
The row cache saves even more time, but must contain the entire row,
so it is extremely space-intensive. It’s best to only use the
row cache if you have hot rows or static rows.
NOTE: if you reduce the size, you may not get you hottest keys loaded on startup.
Default value is empty to make it “auto” (min(5% of Heap (in MB), 100MB)). Set to 0 to disable key cache.
key_cache_size_in_mb:
Duration in seconds after which Cassandra should
save the key cache. Caches are saved to saved_caches_directory as
specified in this configuration file.
Saved caches greatly improve cold-start speeds, and is relatively cheap in
terms of I/O for the key cache. Row cache saving is much more expensive and
has limited use.
Default is 14400 or 4 hours.
key_cache_save_period: 14400
Number of keys from the key cache to save
Disabled by default, meaning all keys are going to be saved
key_cache_keys_to_save: 100
Row cache implementation class name.
Available implementations:
org.apache.cassandra.cache.OHCProvider Fully off-heap row cache implementation (default).
org.apache.cassandra.cache.SerializingCacheProvider This is the row cache implementation availabile
in previous releases of Cassandra.
row_cache_class_name: org.apache.cassandra.cache.OHCProvider
Maximum size of the row cache in memory.
Please note that OHC cache implementation requires some additional off-heap memory to manage
the map structures and some in-flight memory during operations before/after cache entries can be
accounted against the cache capacity. This overhead is usually small compared to the whole capacity.
Do not specify more memory that the system can afford in the worst usual situation and leave some
headroom for OS block level cache. Do never allow your system to swap.
Default value is 0, to disable row caching.
row_cache_size_in_mb: 0
Duration in seconds after which Cassandra should save the row cache.
Caches are saved to saved_caches_directory as specified in this configuration file.
Saved caches greatly improve cold-start speeds, and is relatively cheap in
terms of I/O for the key cache. Row cache saving is much more expensive and
has limited use.
Default is 0 to disable saving the row cache.
row_cache_save_period: 0
Number of keys from the row cache to save.
Specify 0 (which is the default), meaning all keys are going to be saved
row_cache_keys_to_save: 100
Maximum size of the counter cache in memory.
Counter cache helps to reduce counter locks’ contention for hot counter cells.
In case of RF = 1 a counter cache hit will cause Cassandra to skip the read before
write entirely. With RF > 1 a counter cache hit will still help to reduce the duration
of the lock hold, helping with hot counter cell updates, but will not allow skipping
the read entirely. Only the local (clock, count) tuple of a counter cell is kept
in memory, not the whole counter, so it’s relatively cheap.
NOTE: if you reduce the size, you may not get you hottest keys loaded on startup.
Default value is empty to make it “auto” (min(2.5% of Heap (in MB), 50MB)). Set to 0 to disable counter cache.
NOTE: if you perform counter deletes and rely on low gcgs, you should disable the counter cache.
counter_cache_size_in_mb:
Duration in seconds after which Cassandra should
save the counter cache (keys only). Caches are saved to saved_caches_directory as
specified in this configuration file.
Default is 7200 or 2 hours.
counter_cache_save_period: 7200
Number of keys from the counter cache to save
Disabled by default, meaning all keys are going to be saved
counter_cache_keys_to_save: 100
saved caches
If not set, the default directory is $CASSANDRA_HOME/data/saved_caches.
saved_caches_directory: /var/lib/cassandra/saved_caches
commitlog_sync may be either “periodic” or “batch.”
When in batch mode, Cassandra won’t ack writes until the commit log
has been fsynced to disk. It will wait
commitlog_sync_batch_window_in_ms milliseconds between fsyncs.
This window should be kept short because the writer threads will
be unable to do extra work while waiting. (You may need to increase
concurrent_writes for the same reason.)
commitlog_sync: batch
commitlog_sync_batch_window_in_ms: 2
the other option is “periodic” where writes may be acked immediately
and the CommitLog is simply synced every commitlog_sync_period_in_ms
milliseconds.
commitlog_sync: periodic
commitlog_sync_period_in_ms: 10000
The size of the individual commitlog file segments. A commitlog
segment may be archived, deleted, or recycled once all the data
in it (potentially from each columnfamily in the system) has been
flushed to sstables.
The default size is 32, which is almost always fine, but if you are
archiving commitlog segments (see commitlog_archiving.properties),
then you probably want a finer granularity of archiving; 8 or 16 MB
is reasonable.
commitlog_segment_size_in_mb: 32
Compression to apply to the commit log. If omitted, the commit log
will be written uncompressed. LZ4, Snappy, and Deflate compressors
are supported.
#commitlog_compression:
- class_name: LZ4Compressor
parameters:
-
any class that implements the SeedProvider interface and has a
constructor that takes a Map<String, String> of parameters will do.
seed_provider:
# Addresses of hosts that are deemed contact points.
# Cassandra nodes use this list of hosts to find each other and learn
# the topology of the ring. You must change this if you are running
# multiple nodes!
- class_name: org.apache.cassandra.locator.SimpleSeedProvider
parameters:
# seeds is actually a comma-delimited list of addresses.
# Ex: “,,”
- seeds: “127.0.0.1”
For workloads with more data than can fit in memory, Cassandra’s
bottleneck will be reads that need to fetch data from
disk. “concurrent_reads” should be set to (16 * number_of_drives) in
order to allow the operations to enqueue low enough in the stack
that the OS and drives can reorder them. Same applies to
“concurrent_counter_writes”, since counter writes read the current
values before incrementing and writing them back.
On the other hand, since writes are almost never IO bound, the ideal
number of “concurrent_writes” is dependent on the number of cores in
your system; (8 * number_of_cores) is a good rule of thumb.
concurrent_reads: 32
concurrent_writes: 32
concurrent_counter_writes: 32
Total memory to use for sstable-reading buffers. Defaults to
the smaller of 1/4 of heap or 512MB.
file_cache_size_in_mb: 512
Total permitted memory to use for memtables. Cassandra will stop
accepting writes when the limit is exceeded until a flush completes,
and will trigger a flush based on memtable_cleanup_threshold
If omitted, Cassandra will set both to 1/4 the size of the heap.
memtable_heap_space_in_mb: 2048
memtable_offheap_space_in_mb: 2048
Ratio of occupied non-flushing memtable size to total permitted size
that will trigger a flush of the largest memtable. Larger mct will
mean larger flushes and hence less compaction, but also less concurrent
flush activity which can make it difficult to keep your disks fed
under heavy write load.
memtable_cleanup_threshold defaults to 1 / (memtable_flush_writers + 1)
memtable_cleanup_threshold: 0.11
Specify the way Cassandra allocates and manages memtable memory.
Options are:
heap_buffers: on heap nio buffers
offheap_buffers: off heap (direct) nio buffers
offheap_objects: native memory, eliminating nio buffer heap overhead
memtable_allocation_type: heap_buffers
Total space to use for commit logs on disk.
If space gets above this value, Cassandra will flush every dirty CF
in the oldest segment and remove it. So a small total commitlog space
will tend to cause more flush activity on less-active columnfamilies.
The default value is the smaller of 8192, and 1/4 of the total space
of the commitlog volume.
commitlog_total_space_in_mb: 8192
This sets the amount of memtable flush writer threads. These will
be blocked by disk io, and each one will hold a memtable in memory
while blocked.
memtable_flush_writers defaults to the smaller of (number of disks,
number of cores), with a minimum of 2 and a maximum of 8.
If your data directories are backed by SSD, you should increase this
to the number of cores.
#memtable_flush_writers: 8
A fixed memory pool size in MB for for SSTable index summaries. If left
empty, this will default to 5% of the heap size. If the memory usage of
all index summaries exceeds this limit, SSTables with low read rates will
shrink their index summaries in order to meet this limit. However, this
is a best-effort process. In extreme conditions Cassandra may need to use
more than this amount of memory.
index_summary_capacity_in_mb:
How frequently index summaries should be resampled. This is done
periodically to redistribute memory from the fixed-size pool to sstables
proportional their recent read rates. Setting to -1 will disable this
process, leaving existing index summaries at their current sampling level.
index_summary_resize_interval_in_minutes: 60
Whether to, when doing sequential writing, fsync() at intervals in
order to force the operating system to flush the dirty
buffers. Enable this to avoid sudden dirty buffer flushing from
impacting read latencies. Almost always a good idea on SSDs; not
necessarily on platters.
trickle_fsync: false
trickle_fsync_interval_in_kb: 10240
TCP port, for commands and data
For security reasons, you should not expose this port to the internet. Firewall it if needed.
storage_port: 7000
SSL port, for encrypted communication. Unused unless enabled in
encryption_options
For security reasons, you should not expose this port to the internet. Firewall it if needed.
ssl_storage_port: 7001
Address or interface to bind to and tell other Cassandra nodes to connect to.
You must change this if you want multiple nodes to be able to communicate!
Set listen_address OR listen_interface, not both. Interfaces must correspond
to a single address, IP aliasing is not supported.
Leaving it blank leaves it up to InetAddress.getLocalHost(). This
will always do the Right Thing if the node is properly configured
(hostname, name resolution, etc), and the Right Thing is to use the
address associated with the hostname (it might not be).
Setting listen_address to 0.0.0.0 is always wrong.
If you choose to specify the interface by name and the interface has an ipv4 and an ipv6 address
you can specify which should be chosen using listen_interface_prefer_ipv6. If false the first ipv4
address will be used. If true the first ipv6 address will be used. Defaults to false preferring
ipv4. If there is only one address it will be selected regardless of ipv4/ipv6.
listen_address: localhost
listen_interface: eth0
listen_interface_prefer_ipv6: false
Address to broadcast to other Cassandra nodes
Leaving this blank will set it to the same value as listen_address
broadcast_address: 1.2.3.4
When using multiple physical network interfaces, set this
to true to listen on broadcast_address in addition to
the listen_address, allowing nodes to communicate in both
interfaces.
Ignore this property if the network configuration automatically
routes between the public and private networks such as EC2.
listen_on_broadcast_address: false
Internode authentication backend, implementing IInternodeAuthenticator;
used to allow/disallow connections from peer nodes.
internode_authenticator: org.apache.cassandra.auth.AllowAllInternodeAuthenticator
Whether to start the native transport server.
Please note that the address on which the native transport is bound is the
same as the rpc_address. The port however is different and specified below.
start_native_transport: true
port for the CQL native transport to listen for clients on
For security reasons, you should not expose this port to the internet. Firewall it if needed.
native_transport_port: 9042
The maximum threads for handling requests when the native transport is used.
This is similar to rpc_max_threads though the default differs slightly (and
there is no native_transport_min_threads, idle threads will always be stopped
after 30 seconds).
native_transport_max_threads: 128
The maximum size of allowed frame. Frame (requests) larger than this will
be rejected as invalid. The default is 256MB.
native_transport_max_frame_size_in_mb: 256
The maximum number of concurrent client connections.
The default is -1, which means unlimited.
native_transport_max_concurrent_connections: -1
The maximum number of concurrent client connections per source ip.
The default is -1, which means unlimited.
native_transport_max_concurrent_connections_per_ip: -1
Whether to start the thrift rpc server.
start_rpc: true
The address or interface to bind the Thrift RPC service and native transport
server to.
Set rpc_address OR rpc_interface, not both. Interfaces must correspond
to a single address, IP aliasing is not supported.
Leaving rpc_address blank has the same effect as on listen_address
(i.e. it will be based on the configured hostname of the node).
Note that unlike listen_address, you can specify 0.0.0.0, but you must also
set broadcast_rpc_address to a value other than 0.0.0.0.
For security reasons, you should not expose this port to the internet. Firewall it if needed.
If you choose to specify the interface by name and the interface has an ipv4 and an ipv6 address
you can specify which should be chosen using rpc_interface_prefer_ipv6. If false the first ipv4
address will be used. If true the first ipv6 address will be used. Defaults to false preferring
ipv4. If there is only one address it will be selected regardless of ipv4/ipv6.
rpc_address: localhost
rpc_interface: eth1
rpc_interface_prefer_ipv6: false
port for Thrift to listen for clients on
rpc_port: 9160
RPC address to broadcast to drivers and other Cassandra nodes. This cannot
be set to 0.0.0.0. If left blank, this will be set to the value of
rpc_address. If rpc_address is set to 0.0.0.0, broadcast_rpc_address must
be set.
broadcast_rpc_address: 1.2.3.4
enable or disable keepalive on rpc/native connections
rpc_keepalive: true
Cassandra provides two out-of-the-box options for the RPC Server:
sync → One thread per thrift connection. For a very large number of clients, memory
will be your limiting factor. On a 64 bit JVM, 180KB is the minimum stack size
per thread, and that will correspond to your use of virtual memory (but physical memory
may be limited depending on use of stack space).
hsha → Stands for “half synchronous, half asynchronous.” All thrift clients are handled
asynchronously using a small number of threads that does not vary with the amount
of thrift clients (and thus scales well to many clients). The rpc requests are still
synchronous (one thread per active request). If hsha is selected then it is essential
that rpc_max_threads is changed from the default value of unlimited.
The default is sync because on Windows hsha is about 30% slower. On Linux,
sync/hsha performance is about the same, with hsha of course using less memory.
Alternatively, can provide your own RPC server by providing the fully-qualified class name
of an o.a.c.t.TServerFactory that can create an instance of it.
rpc_server_type: sync
Uncomment rpc_min|max_thread to set request pool size limits.
Regardless of your choice of RPC server (see above), the number of maximum requests in the
RPC thread pool dictates how many concurrent requests are possible (but if you are using the sync
RPC server, it also dictates the number of clients that can be connected at all).
The default is unlimited and thus provides no protection against clients overwhelming the server. You are
encouraged to set a maximum that makes sense for you in production, but do keep in mind that
rpc_max_threads represents the maximum number of client requests this server may execute concurrently.
rpc_min_threads: 16
rpc_max_threads: 2048
uncomment to set socket buffer sizes on rpc connections
rpc_send_buff_size_in_bytes:
rpc_recv_buff_size_in_bytes:
Uncomment to set socket buffer size for internode communication
Note that when setting this, the buffer size is limited by net.core.wmem_max
and when not setting it it is defined by net.ipv4.tcp_wmem
See:
/proc/sys/net/core/wmem_max
/proc/sys/net/core/rmem_max
/proc/sys/net/ipv4/tcp_wmem
/proc/sys/net/ipv4/tcp_wmem
and: man tcp
internode_send_buff_size_in_bytes:
internode_recv_buff_size_in_bytes:
Frame size for thrift (maximum message length).
thrift_framed_transport_size_in_mb: 15
Set to true to have Cassandra create 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.
incremental_backups: false
Whether or not to take a snapshot before each compaction. Be
careful using this option, since Cassandra won’t clean up the
snapshots for you. Mostly useful if you’re paranoid when there
is a data format change.
snapshot_before_compaction: false
Whether or not a snapshot is taken of the data before keyspace truncation
or dropping of column families. The STRONGLY advised default of true
should be used to provide data safety. If you set this flag to false, you will
lose data on truncation or drop.
auto_snapshot: true
When executing a scan, within or across a partition, we need to keep the
tombstones seen in memory so we can return them to the coordinator, which
will use them to make sure other replicas also know about the deleted rows.
With workloads that generate a lot of tombstones, this can cause performance
problems and even exaust the server heap.
Adjust the thresholds here if you understand the dangers and want to
scan more tombstones anyway. These thresholds may also be adjusted at runtime
using the StorageService mbean.
tombstone_warn_threshold: 1000
tombstone_failure_threshold: 100000
Granularity of the collation index of rows within a partition.
Increase if your rows are large, or if you have a very large
number of rows per partition. The competing goals are these:
1) a smaller granularity means more index entries are generated
and looking up rows withing the partition by collation column
is faster
2) but, Cassandra will keep the collation index in memory for hot
rows (as part of the key cache), so a larger granularity means
you can cache more hot rows
column_index_size_in_kb: 64
Log WARN on any batch size exceeding this value. 5kb per batch by default.
Caution should be taken on increasing the size of this threshold as it can lead to node instability.
batch_size_warn_threshold_in_kb: 5
Fail any batch exceeding this value. 50kb (10x warn threshold) by default.
batch_size_fail_threshold_in_kb: 50
Log WARN on any batches not of type LOGGED than span across more partitions than this limit
unlogged_batch_across_partitions_warn_threshold: 10
Number of simultaneous compactions to allow, NOT including
validation “compactions” for anti-entropy repair. Simultaneous
compactions can help preserve read performance in a mixed read/write
workload, by mitigating the tendency of small sstables to accumulate
during a single long running compactions. The default is usually
fine and if you experience problems with compaction running too
slowly or too fast, you should look at
compaction_throughput_mb_per_sec first.
concurrent_compactors defaults to the smaller of (number of disks,
number of cores), with a minimum of 2 and a maximum of 8.
If your data directories are backed by SSD, you should increase this
to the number of cores.
#concurrent_compactors: 1
Throttles compaction to the given total throughput across the entire
system. The faster you insert data, the faster you need to compact in
order to keep the sstable count down, but in general, setting this to
16 to 32 times the rate you are inserting data is more than sufficient.
Setting this to 0 disables throttling. Note that this account for all types
of compaction, including validation compaction.
compaction_throughput_mb_per_sec: 16
Log a warning when compacting partitions larger than this value
compaction_large_partition_warning_threshold_mb: 100
When compacting, the replacement sstable(s) can be opened before they
are completely written, and used in place of the prior sstables for
any range that has been written. This helps to smoothly transfer reads
between the sstables, reducing page cache churn and keeping hot rows hot
sstable_preemptive_open_interval_in_mb: 50
Throttles all outbound streaming file transfers on this node to the
given total throughput in Mbps. This is necessary because Cassandra does
mostly sequential IO when streaming data during bootstrap or repair, which
can lead to saturating the network connection and degrading rpc performance.
When unset, the default is 200 Mbps or 25 MB/s.
stream_throughput_outbound_megabits_per_sec: 200
Throttles all streaming file transfer between the datacenters,
this setting allows users to throttle inter dc stream throughput in addition
to throttling all network stream traffic as configured with
stream_throughput_outbound_megabits_per_sec
When unset, the default is 200 Mbps or 25 MB/s
inter_dc_stream_throughput_outbound_megabits_per_sec: 200
How long the coordinator should wait for read operations to complete
read_request_timeout_in_ms: 5000
How long the coordinator should wait for seq or index scans to complete
range_request_timeout_in_ms: 10000
How long the coordinator should wait for writes to complete
write_request_timeout_in_ms: 2000
How long the coordinator should wait for counter writes to complete
counter_write_request_timeout_in_ms: 5000
How long a coordinator should continue to retry a CAS operation
that contends with other proposals for the same row
cas_contention_timeout_in_ms: 1000
How long the coordinator should wait for truncates to complete
(This can be much longer, because unless auto_snapshot is disabled
we need to flush first so we can snapshot before removing the data.)
truncate_request_timeout_in_ms: 60000
The default timeout for other, miscellaneous operations
request_timeout_in_ms: 10000
Enable operation timeout information exchange between nodes to accurately
measure request timeouts. If disabled, replicas will assume that requests
were forwarded to them instantly by the coordinator, which means that
under overload conditions we will waste that much extra time processing
already-timed-out requests.
Warning: before enabling this property make sure to ntp is installed
and the times are synchronized between the nodes.
cross_node_timeout: false
Set socket timeout for streaming operation.
The stream session is failed if no data/ack is received by any of the participants
within that period, which means this should also be sufficient to stream a large
sstable or rebuild table indexes.
Default value is 86400000ms, which means stale streams timeout after 24 hours.
A value of zero means stream sockets should never time out.
streaming_socket_timeout_in_ms: 86400000
phi value that must be reached for a host to be marked down.
most users should never need to adjust this.
phi_convict_threshold: 8
endpoint_snitch – Set this to a class that implements
IEndpointSnitch. The snitch has two functions:
- it teaches Cassandra enough about your network topology to route
requests efficiently
- it allows Cassandra to spread replicas around your cluster to avoid
correlated failures. It does this by grouping machines into
“datacenters” and “racks.” Cassandra will do its best not to have
more than one replica on the same “rack” (which may not actually
be a physical location)
CASSANDRA WILL NOT ALLOW YOU TO SWITCH TO AN INCOMPATIBLE SNITCH
ONCE DATA IS INSERTED INTO THE CLUSTER. This would cause data loss.
This means that if you start with the default SimpleSnitch, which
locates every node on “rack1” in “datacenter1”, your only options
if you need to add another datacenter are GossipingPropertyFileSnitch
(and the older PFS). From there, if you want to migrate to an
incompatible snitch like Ec2Snitch you can do it by adding new nodes
under Ec2Snitch (which will locate them in a new “datacenter”) and
decommissioning the old ones.
Out of the box, Cassandra provides
- SimpleSnitch:
Treats Strategy order as proximity. This can improve cache
locality when disabling read repair. Only appropriate for
single-datacenter deployments.
- GossipingPropertyFileSnitch
This should be your go-to snitch for production use. The rack
and datacenter for the local node are defined in
cassandra-rackdc.properties and propagated to other nodes via
gossip. If cassandra-topology.properties exists, it is used as a
fallback, allowing migration from the PropertyFileSnitch.
- PropertyFileSnitch:
Proximity is determined by rack and data center, which are
explicitly configured in cassandra-topology.properties.
- Ec2Snitch:
Appropriate for EC2 deployments in a single Region. Loads Region
and Availability Zone information from the EC2 API. The Region is
treated as the datacenter, and the Availability Zone as the rack.
Only private IPs are used, so this will not work across multiple
Regions.
- Ec2MultiRegionSnitch:
Uses public IPs as broadcast_address to allow cross-region
connectivity. (Thus, you should set seed addresses to the public
IP as well.) You will need to open the storage_port or
ssl_storage_port on the public IP firewall. (For intra-Region
traffic, Cassandra will switch to the private IP after
establishing a connection.)
- RackInferringSnitch:
Proximity is determined by rack and data center, which are
assumed to correspond to the 3rd and 2nd octet of each node’s IP
address, respectively. Unless this happens to match your
deployment conventions, this is best used as an example of
writing a custom Snitch class and is provided in that spirit.
You can use a custom Snitch by setting this to the full class name
of the snitch, which will be assumed to be on your classpath.
endpoint_snitch: SimpleSnitch
controls how often to perform the more expensive part of host score
calculation
dynamic_snitch_update_interval_in_ms: 100
controls how often to reset all host scores, allowing a bad host to
possibly recover
dynamic_snitch_reset_interval_in_ms: 600000
if set greater than zero and read_repair_chance is < 1.0, this will allow
‘pinning’ of replicas to hosts in order to increase cache capacity.
The badness threshold will control how much worse the pinned host has to be
before the dynamic snitch will prefer other replicas over it. This is
expressed as a double which represents a percentage. Thus, a value of
0.2 means Cassandra would continue to prefer the static snitch values
until the pinned host was 20% worse than the fastest.
dynamic_snitch_badness_threshold: 0.1
request_scheduler – Set this to a class that implements
RequestScheduler, which will schedule incoming client requests
according to the specific policy. This is useful for multi-tenancy
with a single Cassandra cluster.
NOTE: This is specifically for requests from the client and does
not affect inter node communication.
org.apache.cassandra.scheduler.NoScheduler - No scheduling takes place
org.apache.cassandra.scheduler.RoundRobinScheduler - Round robin of
client requests to a node with a separate queue for each
request_scheduler_id. The scheduler is further customized by
request_scheduler_options as described below.
request_scheduler: org.apache.cassandra.scheduler.NoScheduler
Scheduler Options vary based on the type of scheduler
NoScheduler - Has no options
RoundRobin
- throttle_limit – The throttle_limit is the number of in-flight
requests per client. Requests beyond
that limit are queued up until
running requests can complete.
The value of 80 here is twice the number of
concurrent_reads + concurrent_writes.
- default_weight – default_weight is optional and allows for
overriding the default which is 1.
- weights – Weights are optional and will default to 1 or the
overridden default_weight. The weight translates into how
many requests are handled during each turn of the
RoundRobin, based on the scheduler id.
request_scheduler_options:
throttle_limit: 80
default_weight: 5
weights:
Keyspace1: 1
Keyspace2: 5
request_scheduler_id – An identifier based on which to perform
the request scheduling. Currently the only valid option is keyspace.
request_scheduler_id: keyspace
Enable or disable inter-node encryption
Default settings are TLS v1, RSA 1024-bit keys (it is imperative that
users generate their own keys) TLS_RSA_WITH_AES_128_CBC_SHA as the cipher
suite for authentication, key exchange and encryption of the actual data transfers.
Use the DHE/ECDHE ciphers if running in FIPS 140 compliant mode.
NOTE: No custom encryption options are enabled at the moment
The available internode options are : all, none, dc, rack
If set to dc cassandra will encrypt the traffic between the DCs
If set to rack cassandra will encrypt the traffic between the racks
The passwords used in these options must match the passwords used when generating
the keystore and truststore. For instructions on generating these files, see:
server_encryption_options:
internode_encryption: none
keystore: conf/.keystore
keystore_password: cassandra
truststore: conf/.truststore
truststore_password: cassandra
# More advanced defaults below:
# protocol: TLS
# algorithm: SunX509
# store_type: JKS
# cipher_suites: [TLS_RSA_WITH_AES_128_CBC_SHA,TLS_RSA_WITH_AES_256_CBC_SHA,TLS_DHE_RSA_WITH_AES_128_CBC_SHA,TLS_DHE_RSA_WITH_AES_256_CBC_SHA,TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA]
# require_client_auth: false
enable or disable client/server encryption.
client_encryption_options:
enabled: false
# If enabled and optional is set to true encrypted and unencrypted connections are handled.
optional: false
keystore: conf/.keystore
keystore_password: cassandra
# require_client_auth: false
# Set trustore and truststore_password if require_client_auth is true
# truststore: conf/.truststore
# truststore_password: cassandra
# More advanced defaults below:
# protocol: TLS
# algorithm: SunX509
# store_type: JKS
# cipher_suites: [TLS_RSA_WITH_AES_128_CBC_SHA,TLS_RSA_WITH_AES_256_CBC_SHA,TLS_DHE_RSA_WITH_AES_128_CBC_SHA,TLS_DHE_RSA_WITH_AES_256_CBC_SHA,TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA]
internode_compression controls whether traffic between nodes is
compressed.
can be: all - all traffic is compressed
dc - traffic between different datacenters is compressed
none - nothing is compressed.
internode_compression: all
Enable or disable tcp_nodelay for inter-dc communication.
Disabling it will result in larger (but fewer) network packets being sent,
reducing overhead from the TCP protocol itself, at the cost of increasing
latency if you block for cross-datacenter responses.
inter_dc_tcp_nodelay: false
TTL for different trace types used during logging of the repair process.
tracetype_query_ttl: 86400
tracetype_repair_ttl: 604800
By default, Cassandra logs GC Pauses greater than 200 ms at INFO level
This threshold can be adjusted to minimize logging if necessary
gc_log_threshold_in_ms: 200
GC Pauses greater than gc_warn_threshold_in_ms will be logged at WARN level
If unset, all GC Pauses greater than gc_log_threshold_in_ms will log at
INFO level
Adjust the threshold based on your application throughput requirement
gc_warn_threshold_in_ms: 1000
UDFs (user defined functions) are disabled by default.
As of Cassandra 2.2, there is no security manager or anything else in place that
prevents execution of evil code. CASSANDRA-9402 will fix this issue for Cassandra 3.0.
This will inherently be backwards-incompatible with any 2.2 UDF that perform insecure
operations such as opening a socket or writing to the filesystem.
enable_user_defined_functions: false
The default Windows kernel timer and scheduling resolution is 15.6ms for power conservation.
Lowering this value on Windows can provide much tighter latency and better throughput, however
some virtualized environments may see a negative performance impact from changing this setting
below their system default. The sysinternals ‘clockres’ tool can confirm your system’s default
setting.
windows_timer_interval: 1
Maximum size of any value in SSTables. Safety measure to detect SSTable corruption
early. Any value size larger than this threshold will result into marking an SSTable
as corrupted.
max_value_size_in_mb: 256
Coalescing Strategies
Coalescing multiples messages turns out to significantly boost message processing throughput (think doubling or more).
On bare metal, the floor for packet processing throughput is high enough that many applications won’t notice, but in
virtualized environments, the point at which an application can be bound by network packet processing can be
surprisingly low compared to the throughput of task processing that is possible inside a VM. It’s not that bare metal
doesn’t benefit from coalescing messages, it’s that the number of packets a bare metal network interface can process
is sufficient for many applications such that no load starvation is experienced even without coalescing.
There are other benefits to coalescing network messages that are harder to isolate with a simple metric like messages
per second. By coalescing multiple tasks together, a network thread can process multiple messages for the cost of one
trip to read from a socket, and all the task submission work can be done at the same time reducing context switching
and increasing cache friendliness of network message processing.
See CASSANDRA-8692 for details.
Strategy to use for coalescing messages in OutboundTcpConnection.
Can be fixed, movingaverage, timehorizon (default), disabled.
You can also specify a subclass of CoalescingStrategies.CoalescingStrategy by name.
otc_coalescing_strategy: TIMEHORIZON
How many microseconds to wait for coalescing. For fixed strategy this is the amount of time after the first
message is received before it will be sent with any accompanying messages. For moving average this is the
maximum amount of time that will be waited as well as the interval at which messages must arrive on average
for coalescing to be enabled.
otc_coalescing_window_us: 200
Do not try to coalesce messages if we already got that many messages. This should be more than 2 and less than 128.
otc_coalescing_enough_coalesced_messages: 8
