IBM Storage Scale port usage

The nodes in an IBM Storage Scale cluster communicate with each other using the TCP/IP protocol. The port number used by the main GPFS daemon (mmfsd) is controlled with the tscTcpPort configuration parameter. The default port number is 1191.

You can specify a different port number by using the mmchconfig command:

mmchconfig tscTcpPort=PortNumber

When the main GPFS daemon (mmfsd) is not running , a separate service (mmsdrserv) is used to provide access to the configuration data. The port number used for this purpose is controlled with the mmsdrservPort (tscTcpPort) parameter. The mmsdrserv daemon uses the same port number as the one assigned to the main GPFS daemon.

Certain commands (mmadddisk, mmchmgr, and so on) require an additional socket to be created for the duration of the command. The port numbers assigned to these temporary sockets are controlled with the tscCmdPortRange configuration parameter. If an explicit range is not specified, the port number is dynamically assigned by the operating system from the range of ephemeral port numbers. If you want to restrict the range of ports used by IBM Storage Scale commands, use the mmchconfig command:

mmchconfig tscCmdPortRange=LowNumber-HighNumber

In a remote cluster setup, if IBM Storage Scale on the remote cluster is configured to use a port number other than the default, you have to specify the port number to be used with the mmremotecluster command:

mmremotecluster update ClusterName -n tcpPort=PortNumber,Node,Node...

For related information, see the topic Firewall recommendations for internal communication among nodes.

Table 1 provides IBM Storage Scale port usage information:

Table 1. IBM Storage Scale port usage
Descriptor	Explanation
Service provider	IBM Storage Scale
Service name	mmfsd mmsdrserv
Port number	1191 While executing certain commands, IBM Storage Scale may need to create additional sockets whose dynamic port numbers are assigned by the operating system. Such sockets are used by commands to exchange data with GPFS daemons running on other nodes. The port numbers that are used correspond to the ephemeral ports of the operating system. To control which ports are used by the commands (so that firewall rules can be written to allow incoming traffic only on those ports), you can restrict the port range to a specific range by setting the tscCmdPortRange configuration variable.
Protocols	TCP/IP
Source port range	The source port range is chosen by the operating system on the client side.
Is the service name/number pair in the default /etc/services file shipped with AIX® and Linux® distributions?	See the IBM Storage Scale FAQ in IBM® Documentation.
Is the service name/number pair added to /etc/services by a product?	No
Binaries that listen on the ports	/usr/lpp/mmfs/bin/mmfsd /usr/lpp/mmfs/bin/mmsdrserv
Can the service be configured to use a different port?	Yes. To change the main port used by IBM Storage Scale, enter: `mmchconfig tscTcpPort=PortNumber` To change the range of port numbers used for command execution, use: `mmchconfig tscCmdPortRange=LowNumber-HighNumber` To specify a port number when connecting to remote clusters, use the mmremotecluster command.
When the daemon starts and its port is already in use (for example, another resource has bound to it already), how does the daemon behave?	The daemon shuts down and tries to start over again. Most GPFS daemon down error messages are in the mmfs.log.previous log for the instance that failed. If the daemon restarted, it generates a new mmfs.log.latest log. Begin problem determination for these errors by examining the operating system error log. IBM Storage Scale records file system or disk failures using the error logging facility provided by the operating system: syslog facility on Linux and errpt facility on AIX. See the IBM Storage Scale: Problem Determination Guide for further information.
Is there an administrator interface to query the daemon and have it report its port number?	Yes; issue this command: `mmlsconfig tscTcpPort`
Is the service/port registered with the Internet Assigned Numbers Authority (IANA)?	Yes `gpfs 1191/tcp General Parallel File System gpfs 1191/udp General Parallel File System # Dave Craft <gpfs@ibm.com> November 2004`

Note: Ports configured for the IBM Storage Scale remote shell command (such as ssh) or the remote file copy command (such as scp) and the ICMP echo command (network ping) also must be unblocked in the firewall for IBM Storage Scale to function properly.