Index of wsrep_provider options

You can set and check the following options in the wsrep_provider_options system variable. You can change option values in the MySQL configuration file, my.cnf, or by setting options in the MySQL client.

To change the value in my.cnf, use the following syntax:

wsrep_provider_options="option1=value1;[option2=value2]"

For example, to set the size of the Galera buffer storage (gcache) to 512 MB, specify the following in my.cnf:

wsrep_provider_options="gcache.size=512M"

You can change dynamic options from the MySQL client using the SET GLOBAL command (for example, SET GLOBAL wsrep_provider_options="option=value";). For each option below, only the config file syntax is shown; options with Dynamic: Yes in the table can also be set at runtime in the same way.

Index

base_dir

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	value of datadir

This option specifies the data directory.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="base_dir=/var/lib/mysql"

base_host

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	value of wsrep_node_address

This option sets the value of the node’s base IP. This is an IP address on which Galera listens for connections from other nodes. Setting this value incorrectly would stop the node from communicating with other nodes.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="base_host=/var/lib/mysql"

base_port

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	4567

This option sets the port on which Galera listens for connections from other nodes. Setting this value incorrectly would stop the node from communicating with other nodes.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="base_port=4567"

cert.log_conflicts

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	no

This option specifies whether the cluster logs the details of certification failures.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="cert.log_conflicts=yes"

cert.optimistic_pa

This option controls whether parallel applying of replicated transactions is optimistic (allowed to run ahead of the source) or conservative (limited to the source’s apply window). The default is No (Disabled).

Enabled (Yes): Allows the full range of parallelization as determined by the certification algorithm.

Disabled (No, default): Limits the parallel applying window so that the window does not exceed the parallel applying window seen on the source. In this case, the action starts applying no sooner than all actions on the source are committed.

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	Yes
Default Value:	No

debug

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	Yes
Default Value:	no

When you set this option to yes, debugging is enabled.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="debug=yes"

evs.auto_evict

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	Yes
Default Value:	0

This option specifies the number of entries allowed on the delayed list until auto eviction runs. Set the value to 0 to disable auto eviction on the node (the cluster still monitors node response times). Auto eviction requires EVS (Extended Virtual Synchrony) protocol version (evs.version) 1.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.auto_evict=5"

evs.causal_keepalive_period

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	value of evs.keepalive_period

Use this option only for development. Do not use the option in production.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.causal_keepalive_period=/var/lib/mysql"

evs.debug_log_mask

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	Yes
Default Value:	0x1

Use this option for EVS (Extended Virtual Synchrony) debugging. You can use the option only when wsrep_debug is set to ON.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.debug_log_mask=0x1"

evs.delay_margin

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	Yes
Default Value:	PT1S

This option specifies the time period that a node can delay its response from expected before the node is added to the delayed list. The value must be higher than the highest RTT (round-trip time) between nodes.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.delay_margin=PT30S"

evs.delayed_keep_period

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	Yes
Default Value:	PT30S

This option specifies the time period that a node must remain responsive before one entry is removed from the delayed list.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.delayed_keep_period=PT30S"

evs.evict

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	Yes

Manual eviction can be triggered by setting the evs.evict to a certain node value. Setting the evs.evict to an empty string will clear the evict list on the node where the option was set.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.evict=value"

evs.inactive_check_period

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	PT0.5S

This option defines how often to check for peer inactivity.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.inactive_check_period=PT30S"

evs.inactive_timeout

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	PT15S

This option defines the inactivity limit. Once the cluster reaches this limit, the cluster considers the node dead.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.inactive_timeout=PT30S"

evs.info_log_mask

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	0

This option controls extra EVS (Extended Virtual Synchrony) info logging.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.info_log_mask=0"

evs.install_timeout

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	Yes
Default Value:	PT7.5S

This option defines the timeout on waiting for install message acknowledgments.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.install_timeout=PT30S"

evs.join_retrans_period

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	PT1S

This option defines how often to retransmit EVS (Extended Virtual Synchrony) join messages when forming cluster membership.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.join_retrans_period=PT30S"

evs.keepalive_period

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	PT1S

This option defines how often to emit keepalive beacons (in the absence of any other traffic).

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.keepalive_period=PT30S"

evs.max_install_timeouts

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	1

This option defines how many membership install rounds to try before giving up (total rounds will be evs.max_install_timeouts + 2).

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.max_install_timeouts=1"

evs.send_window

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	10

This option defines the maximum number of data packets in replication at a time. For WAN setups, you can set this option to a considerably higher value than the default (for example, 512). The value must not be less than evs.user_send_window.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.send_window=10"

evs.stats_report_period

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	PT1M

This option defines the control period of EVS (Extended Virtual Synchrony) statistics reporting.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.stats_report_period=PT1M"

evs.suspect_timeout

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	Yes
Default Value:	PT5S

This option defines the inactivity period after which the node is “suspected” to be dead. If all remaining nodes agree, the cluster drops the node even before evs.inactive_timeout is reached.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.suspect_timeout=PT30S"

evs.use_aggregate

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	true

When you enable this option, the cluster aggregates smaller packets into one.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.use_aggregate=no"

evs.user_send_window

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	Yes
Default Value:	4

This option defines the maximum number of data packets in replication at a time. For WAN setups, you can set this option to a considerably higher value than the default (for example, 512).

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.user_send_window=4"

evs.version

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	0

This option defines the EVS (Extended Virtual Synchrony) protocol version. Setting this option to 1 enables auto eviction. The default 0 keeps backwards compatibility.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.version=0"

evs.view_forget_timeout

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	P1D

This option defines the timeout after which the cluster drops past views from history.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="evs.view_forget_timeout=P1D"

gcache.dir

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	datadir

Use this option to define the location of the galera.cache file.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcache.dir=/var/lib/mysql"

gcache.freeze_purge_at_seqno

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Local, Global
Dynamic:	Yes
Default Value:	-1

This option controls the purging of the gcache (Galera cache) and enables retaining more data in the gcache. This option makes possible the use of IST (Incremental State Transfer) when the node rejoins instead of SST (State Snapshot Transfer).

Set this option on an existing node of the cluster (that will continue to be part of the cluster and can act as a potential donor node). This node continues to retain the write-sets (replicated transaction data) and allows restarting the node to rejoin by using IST.

See also

Percona Database Performance Blog:

• All You Need to Know About GCache (Galera-Cache)

• Want IST Not SST for Node Rejoins? We Have a Solution!

The gcache.freeze_purge_at_seqno option accepts one of the following:

-1 (default): No freezing of gcache; purge operates as normal.

A numeric sequence number (seqno): The freeze purge of write-sets may not be smaller than the chosen seqno. To choose a value, use the status variable :variable:wsrep_last_applied on the node that you plan to shut down.

The literal string now: Set the value to the word now (as a string, not a number). The freeze purge of write-sets is then no less than the smallest seqno currently in gcache, which freezes the gcache purge immediately. Use now when picking a specific seqno is impractical.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcache.freeze_purge_at_seqno=-1"

To freeze purge immediately using the current minimum seqno:

wsrep_provider_options="gcache.freeze_purge_at_seqno=now"

gcache.keep_pages_count

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Local, Global
Dynamic:	Yes
Default Value:	0

This option limits the number of overflow pages rather than the total memory occupied by all overflow pages. Whenever you set gcache.keep_pages_count to a non-zero value, the cluster deletes excess overflow pages (starting from the oldest to the newest).

Whenever you update either gcache.keep_pages_count or gcache.keep_pages_size at runtime to a non-zero value, the cluster runs cleanup and deletes excess overflow pages.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcache.keep_pages_count=0"

gcache.keep_pages_size

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Local, Global
Dynamic:	No
Default Value:	0

This option limits the total size of overflow pages rather than the count of all overflow pages. Whenever you set gcache.keep_pages_size to a non-zero value, the cluster deletes excess overflow pages (starting from the oldest to the newest) until the total size is below the specified value.

Whenever you update either gcache.keep_pages_count or gcache.keep_pages_size at runtime to a non-zero value, the cluster runs cleanup and deletes excess overflow pages.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcache.keep_pages_size=0"

gcache.mem_size

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	0

This option has been deprecated in 5.6.22-25.8 and shouldn’t be used because the option could cause a node to crash.

This option was used to define how much RAM is available for the system.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcache.mem_size=0"

gcache.name

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	/var/lib/mysql/galera.cache

Use this option to specify the name of the Galera cache file.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcache.name=/var/lib/mysql/galera.cache"

gcache.page_size

Option	Description
Command Line:	No
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	128M

Size of the page files in page storage. The limit on overall page storage is the size of the disk. Page file names use the gcache.page prefix.

See also

Percona Database Performance Blog: All You Need to Know About GCache

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcache.page_size=128M"

gcache.recover

Option	Description
Command line:	No
Configuration file:	Yes
Scope:	Global
Dynamic:	No
Default value:	Yes

This option attempts to recover a node’s gcache file to a usable state during startup. If the node successfully recovers the gcache file, the node provides Incremental State Transfer (IST) to the remaining nodes. This capability reduces the time required to bring up the cluster.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcache.recover=value"

gcache.size

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	128M

Size of the transaction cache for Galera replication. This option defines the size of the galera.cache file, which the cluster uses as the source for IST. The higher the value of this option, the better the chance that a re-joining node gets IST instead of SST.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcache.size=512M"

gcomm.thread_prio

Using this option, you can raise the priority of the gcomm thread to a higher level than the thread normally uses.

The format for this option is: <policy>:<priority>. The priority value is an integer.

other

Default time-sharing scheduling in Linux. The threads can run until blocked by an I/O request or preempted by higher priorities or superior scheduling designations.

fifo

First-in First-out (FIFO) scheduling. These threads always immediately preempt any currently running other, batch or idle threads. They can run until they are either blocked by an I/O request or preempted by a FIFO thread of a higher priority.

rr

Round-robin scheduling. These threads always preempt any currently running other, batch or idle threads. The scheduler allows these threads to run for a
fixed period of a time. If the thread is still running when this time period is exceeded, they are stopped and moved to the end of the list, allowing another
round-robin thread of the same priority to run in their place. They can otherwise continue to run until they are blocked by an I/O request or are
preempted by threads of a higher priority.

See also

For information, see the MariaDB Galera Cluster documentation

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcomm.thread_prio=value"

gcs.fc_auto_evict_threshold

Option	Description
Command Line:	Yes
Config file :	Yes
Scope:	Global
Dynamic:	No
Default value:	0.75

This option defines the threshold that the cluster must reach or cross before evicting a node. The option is a ratio of the gcs.fc_auto_evict_window option. The default is .075; you can set the value to any number between 0.0 and 1.0.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcs.fc_auto_evict_threshold=value"

gcs.fc_auto_evict_window

Option	Description
Command Line:	Yes
Config file :	Yes
Scope:	Global
Dynamic:	No
Default value:	0

This option defines the time window width within which the cluster observes flow control. The time span of the window is [now - gcs.fc_audot_evict_window, now]. The window is constantly moving ahead as the time passes. And now, within this window if the flow control summary time >= (gcs.fc_audot-evict_window * gcs.fc_audot_evict_threshold), the node self-leaves the cluster.

The default value is 0, which means that the feature is disabled.

The maximum value is DBL_MAX.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcs.fc_auto_evict_window=value"

gcs.fc_debug

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	0

This option specifies after how many writesets the cluster posts debug statistics about SST (State Snapshot Transfer) flow control.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcs.fc_debug=0"

gcs.fc_factor

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	Yes
Default Value:	1

This option controls replication flow. Replication resumes when the replica queue drops below gcs.fc_factor * gcs.fc_limit.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcs.fc_factor=1"

gcs.fc_limit

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	Yes
Default Value:	100

This option controls replication flow. Replication pauses when the replica queue exceeds this limit. In the default operation mode, the cluster recalculates the flow control limit dynamically based on the number of nodes in the cluster. You can turn off this recalculation by using the gcs.fc_master_slave option so that manual setting of gcs.fc_limit takes effect (e.g., when only one node in Percona XtraDB Cluster accepts writes).

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcs.fc_limit=100"

gcs.fc_master_slave

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	NO
Default Value:	NO

This option specifies if there is only one source node in the cluster. It affects whether flow control limit is recalculated dynamically (when NO) or not (when YES).

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcs.fc_master_slave=NO"

gcs.max_packet_size

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	64500

This option specifies the writeset (replicated transaction data) size after which the cluster fragments them.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcs.max_packet_size=64500"

gcs.max_throttle

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	0.25

This option specifies how much replication can be throttled during state transfer to avoid running out of memory. You can set the value to 0.0 if stopping replication is acceptable to finish state transfer.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcs.max_throttle=0.25"

gcs.recv_q_hard_limit

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	9223372036854775807

This option specifies the maximum allowed size of the receive queue. Set this to (RAM + swap) / 2 in most cases. If the limit is exceeded, Galera aborts the server.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcs.recv_q_hard_limit=9223372036854775807"

gcs.recv_q_soft_limit

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	0.25

This option specifies the fraction of the gcs.recv_q_hard_limit after which the cluster throttles the replication rate.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcs.recv_q_soft_limit=0.25"

gcs.sync_donor

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	No

This option controls whether the rest of the cluster stays in sync with the donor node. When you set this option to YES, the whole cluster blocks if the donor node is blocked with SST (State Snapshot Transfer).

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gcs.sync_donor=yes"

gmcast.listen_addr

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	tcp://0.0.0.0:4567

This option defines the address on which the node listens to connections from other nodes in the cluster.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gmcast.listen_addr=tcp://0.0.0.0:4567"

gmcast.mcast_addr

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	None

Set this option if you use UDP multicast for replication.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gmcast.mcast_addr=None"

gmcast.mcast_ttl

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	1

Use this option to define TTL (time to live) for multicast packets.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gmcast.mcast_ttl=1"

gmcast.peer_timeout

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	PT3S

This option specifies the connection timeout to initiate message relaying.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gmcast.peer_timeout=PT30S"

gmcast.segment

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	0

This option specifies the group segment this member belongs to. The cluster treats members in the same segment as equally physically close.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gmcast.segment=0"

gmcast.time_wait

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	PT5S

This option specifies the time to wait until allowing peer declared outside of stable view to reconnect.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gmcast.time_wait=PT30S"

gmcast.version

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	0

This option shows which gmcast protocol version is being used.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="gmcast.version=0"

ist.recv_addr

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	value of wsrep_node_address

This option specifies the address on which the node listens for Incremental State Transfer (IST).

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="ist.recv_addr=/var/lib/mysql"

pc.announce_timeout

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	PT3S

The node sends cluster joining announcements every half second (0.5 s) for this period or less if the node discovers other nodes.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="pc.announce_timeout=PT30S"

pc.bootstrap

Option	Description
Command Line:	No
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	FALSE

pc.bootstrap is a configuration option that instructs a node to become the initial starting point for a new cluster or rejoin an existing one as the primary component (PC). You can only set this option in the configuration file.

wsrep_provider_options="pc.bootstrap=TRUE"

You can use pc.bootstrap in the following:

Action	Description
Bootstrap a New Cluster	When setting up a new Galera cluster, designate one node as the bootstrap node by setting pc.bootstrap=YES on that node. This allows the node to initialize the cluster and become the primary component. Other nodes can then discover and join this primary node.
Rejoining a Cluster (Use with Caution)	If a Galera node needs to rejoin the cluster as the primary component (for example, after a disconnect or restart), you can use pc.bootstrap=TRUE. This is generally not recommended because bootstrapping can lead to data loss if other cluster nodes made changes while the bootstrapping node was offline.

By default, pc.bootstrap is disabled (FALSE).

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="pc.bootstrap=FALSE"

pc.checksum

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	true

This option controls whether the cluster checksums replicated messages.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="pc.checksum=no"

pc.ignore_quorum

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	false

When you set this option to TRUE, the node completely ignores quorum calculations. Use this option with extreme caution even in source-replica setups, because replicas won’t automatically reconnect to source in this case.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="pc.ignore_quorum=false"

pc.ignore_sb

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	Yes
Default Value:	false

When you set this option to TRUE, the node processes updates even in the case of a split brain. Use this option with extreme caution in multi-source setup, and can simplify things in a source-replica cluster (especially if only two nodes are used).

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="pc.ignore_sb=false"

pc.linger

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	PT20S

This option specifies the period for which the PC (Primary Component) protocol waits for EVS (Extended Virtual Synchrony) termination.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="pc.linger=PT30S"

pc.npvo

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	false

When you set this option to TRUE, more recent primary components override older ones in case of conflicting primaries.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="pc.npvo=false"

pc.recovery

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	true

When you set this option to true, the node stores the Primary Component state to disk. The Primary Component can then recover automatically when all nodes that were part of the last saved state re-establish communication with each other. This feature allows automatic recovery from full cluster crashes, such as in the case of a data center power outage. A subsequent graceful full cluster restart requires explicit bootstrapping for a new Primary Component.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="pc.recovery=no"

pc.version

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	0

Use this option to check which PC (Primary Component) protocol version the cluster uses.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="pc.version=0"

pc.wait_prim

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	true

When set to TRUE, the node waits for a primary component for the period of time specified in pc.wait_prim_timeout. Use this to bring up a non-primary component and make that component primary with pc.bootstrap.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="pc.wait_prim=no"

pc.wait_prim_timeout

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	PT30S

This option specifies the period of time to wait for a primary component.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="pc.wait_prim_timeout=PT30S"

pc.wait_restored_prim_timeout

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic	No
Default Value:	PT0S

This option specifies the wait period for a primary component when the cluster restores the primary component from the gvwstate.dat file after an outage.

The default value is PT0S (zero seconds). The node waits for an infinite time, which is the current behavior.

You can define a wait time with PTNS, replace the N value with the number of seconds. For example, to wait for 90 seconds, set the value to PT90S.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="pc.wait_restored_prim_timeout=PT30S"

pc.weight

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	Yes
Default Value:	1

This option specifies the node weight that’s going to be used for Weighted Quorum calculations.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="pc.weight=1"

protonet.backend

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	asio

This option defines which transport backend to use. Currently the cluster supports only ASIO (Asynchronous I/O library).

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="protonet.backend=asio"

protonet.version

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	0

Use this option to check which transport backend protocol version the cluster uses.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="protonet.version=0"

repl.causal_read_timeout

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	Yes
Default Value:	PT30S

This option specifies the causal read timeout.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="repl.causal_read_timeout=PT30S"

repl.commit_order

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	3

This option specifies out-of-order committing (which improves parallel applying performance). You can use the following values:

• 0 - BYPASS: all commit order monitoring is turned off (useful for measuring performance penalty)

• 1 - OOOC: allow out-of-order committing for all transactions

• 2 - LOCAL_OOOC: allow out-of-order committing only for local transactions

• 3 - NO_OOOC: no out-of-order committing is allowed (strict total order committing)

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="repl.commit_order=3"

repl.key_format

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	Yes
Default Value:	FLAT8

This option specifies the replication key format. You can use the following values:

• FLAT8 - short key with higher probability of key match false positives

• FLAT16 - longer key with lower probability of false positives

• FLAT8A - same as FLAT8 but with annotations for debug purposes

• FLAT16A - same as FLAT16 but with annotations for debug purposes

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="repl.key_format=FLAT8"

repl.max_ws_size

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	2147483647

This option specifies the maximum size of a write-set (replicated transaction data) in bytes. The maximum is 2 gigabytes.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="repl.max_ws_size=2147483647"

repl.proto_max

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	7

This option specifies the highest communication protocol version to accept in the cluster. Use this option only for debugging.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="repl.proto_max=7"

socket.checksum

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	2

This option selects the checksum algorithm for network packets. The CRC32-C option is optimized and may be hardware accelerated on Intel CPUs. You can use the following values:

• 0 - disable checksum

• 1 - plain CRC32 (used in Galera 2.x)

• 2 - hardware accelerated CRC32-C

The following is an example of the option:

wsrep_provider_options="socket.checksum=2"

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="socket.checksum=2"

socket.ssl

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	No

This option specifies whether to use SSL (Secure Sockets Layer) encryption.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="socket.ssl=yes"

socket.ssl_ca

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No

This option specifies the path to the Certificate Authority (CA) certificate file.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="socket.ssl_ca=/path/to/ca.pem"

socket.ssl_cert

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No

This option specifies the path to the server’s certificate file (in PEM, Privacy Enhanced Mail, format).

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="socket.ssl_cert=/path/to/server-cert.pem"

socket.ssl_key

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No

This option specifies the path to the server’s private key file (in PEM, Privacy Enhanced Mail, format).

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="socket.ssl_key=/path/to/server-key.pem"

socket.ssl_compression

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	Yes

This option specifies whether to use SSL (Secure Sockets Layer) compression.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="socket.ssl_compression=no"

socket.ssl_cipher

Option	Description
Command Line:	Yes
Config File:	Yes
Scope:	Global
Dynamic:	No
Default Value:	AES128-SHA

This option specifies which cipher to use for encryption.

Example (config file): Add to the [mysqld] section of my.cnf:

wsrep_provider_options="socket.ssl_cipher=AES128-SHA"