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21.3.3.13 SCI Transport Connections in NDB Cluster

[sci] sections in the config.ini file explicitly define SCI (Scalable Coherent Interface) connections between cluster nodes. Using SCI transporters in NDB Cluster requires specialized hardware as well as specially-built MySQL binaries; compiling such binaries is not supported using an NDB 7.2 or later distribution.

Restart types.  Information about the restart types used by the parameter descriptions in this section is shown in the following table:

Table 21.314 NDB Cluster restart types

Symbol Restart Type Description
N Node The parameter can be updated using a rolling restart (see Section 21.5.5, “Performing a Rolling Restart of an NDB Cluster”)
S System All cluster nodes must be shut down completely, then restarted, to effect a change in this parameter
I Initial Data nodes must be restarted using the --initial option

The following parameters are present in NDB source code as well as the output of ndb_config and other NDB programs, but are nonfunctional in NDB 7.2 and later.

  • NodeId1

    Table 21.315 This table provides type and value information for the NodeId1 SCI configuration parameter

    Property Value
    Version (or later) NDB 7.5.0
    Type or units numeric
    Default [none]
    Range 1 - 255
    Restart Type N

    To identify a connection between two nodes it is necessary to provide node identifiers for each of them, as NodeId1 and NodeId2.

  • NodeId2

    Table 21.316 This table provides type and value information for the NodeId2 SCI configuration parameter

    Property Value
    Version (or later) NDB 7.5.0
    Type or units numeric
    Default [none]
    Range 1 - 255
    Restart Type N

    To identify a connection between two nodes it is necessary to provide node identifiers for each of them, as NodeId1 and NodeId2.

  • Host1SciId0

    Table 21.317 This table provides type and value information for the Host1SciId0 SCI configuration parameter

    Property Value
    Version (or later) NDB 7.5.0
    Type or units unsigned
    Default [none]
    Range 0 - 4294967039 (0xFFFFFEFF)
    Restart Type N

    This identifies the SCI node ID on the first Cluster node (identified by NodeId1).

  • Host1SciId1

    Table 21.318 This table provides type and value information for the Host1SciId1 SCI configuration parameter

    Property Value
    Version (or later) NDB 7.5.0
    Type or units unsigned
    Default 0
    Range 0 - 4294967039 (0xFFFFFEFF)
    Restart Type N

    It is possible to set up SCI Transporters for failover between two SCI cards which then should use separate networks between the nodes. This identifies the node ID and the second SCI card to be used on the first node.

  • Host2SciId0

    Table 21.319 This table provides type and value information for the Host2SciId0 SCI configuration parameter

    Property Value
    Version (or later) NDB 7.5.0
    Type or units unsigned
    Default [none]
    Range 0 - 4294967039 (0xFFFFFEFF)
    Restart Type N

    This identifies the SCI node ID on the second Cluster node (identified by NodeId2).

  • Host2SciId1

    Table 21.320 This table provides type and value information for the Host2SciId1 SCI configuration parameter

    Property Value
    Version (or later) NDB 7.5.0
    Type or units unsigned
    Default 0
    Range 0 - 4294967039 (0xFFFFFEFF)
    Restart Type N

    When using two SCI cards to provide failover, this parameter identifies the second SCI card to be used on the second node.

  • HostName1

    Table 21.321 This table provides type and value information for the HostName1 SCI configuration parameter

    Property Value
    Version (or later) NDB 7.5.0
    Type or units name or IP address
    Default [none]
    Range ...
    Restart Type N

    The HostName1 and HostName2 parameters can be used to specify specific network interfaces to be used for a given SCI connection between two nodes. The values used for these parameters can be host names or IP addresses.

  • HostName2

    Table 21.322 This table provides type and value information for the HostName1 SCI configuration parameter

    Property Value
    Version (or later) NDB 7.5.0
    Type or units name or IP address
    Default [none]
    Range ...
    Restart Type N

    The HostName1 and HostName2 parameters can be used to specify specific network interfaces to be used for a given SCI connection between two nodes. The values used for these parameters can be host names or IP addresses.

  • SharedBufferSize

    Table 21.323 This table provides type and value information for the SharedBufferSize SCI configuration parameter

    Property Value
    Version (or later) NDB 7.5.0
    Type or units unsigned
    Default 10M
    Range 64K - 4294967039 (0xFFFFFEFF)
    Restart Type N

    Each SCI transporter has a shared memory segment used for communication between the two nodes. Setting the size of this segment to the default value of 1MB should be sufficient for most applications. Using a smaller value can lead to problems when performing many parallel inserts; if the shared buffer is too small, this can also result in a crash of the ndbd process.

  • SendLimit

    Table 21.324 This table provides type and value information for the SendLimit SCI configuration parameter

    Property Value
    Version (or later) NDB 7.5.0
    Type or units unsigned
    Default 8K
    Range 128 - 32K
    Restart Type N

    A small buffer in front of the SCI media stores messages before transmitting them over the SCI network. By default, this is set to 8KB. Our benchmarks show that performance is best at 64KB but 16KB reaches within a few percent of this, and there was little if any advantage to increasing it beyond 8KB.

  • SendSignalId

    Table 21.325 This table provides type and value information for the SendSignalId SCI configuration parameter

    Property Value
    Version (or later) NDB 7.5.0
    Type or units boolean
    Default true
    Range true, false
    Restart Type N

    To trace a distributed message it is necessary to identify each message uniquely. When this parameter is set to Y, message IDs are transported over the network. This feature is disabled by default in production builds, and enabled in -debug builds.

  • Checksum

    Table 21.326 This table provides type and value information for the Checksum SCI configuration parameter

    Property Value
    Version (or later) NDB 7.5.0
    Type or units boolean
    Default false
    Range true, false
    Restart Type N

    This parameter is a boolean value, and is disabled by default. When Checksum is enabled, checksums are calculated for all messages before they are placed in the send buffer. This feature prevents messages from being corrupted while waiting in the send buffer. It also serves as a check against data being corrupted during transport.

  • OverloadLimit

    Table 21.327 This table provides type and value information for the OverloadLimit SCI configuration parameter

    Property Value
    Version (or later) NDB 7.5.0
    Type or units bytes
    Default 0
    Range 0 - 4294967039 (0xFFFFFEFF)
    Restart Type N

    When more than this many unsent bytes are in the send buffer, the connection is considered overloaded. See Section 21.3.3.14, “Configuring NDB Cluster Send Buffer Parameters”, for more information.


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