gpaddmirrors

gpaddmirrors

Adds mirror segments to a Greenplum Database system that was initially configured without mirroring.

Synopsis

gpaddmirrors [-p port_offset] [-m datadir_config_file [-a]] [-s] 
   [-d master_data_directory] [-B parallel_processes] [-l logfile_directory]
   [-v]

gpaddmirrors -i mirror_config_file [-a] [-d master_data_directory]
   [-B parallel_processes] [-l logfile_directory] [-v]

gpaddmirrors -o output_sample_mirror_config [-s] [-m datadir_config_file]

gpaddmirrors -? 

gpaddmirrors --version

Description

The gpaddmirrors utility configures mirror segment instances for an existing Greenplum Database system that was initially configured with primary segment instances only. The utility will create the mirror instances and begin the online replication process between the primary and mirror segment instances. Once all mirrors are synchronized with their primaries, your Greenplum Database system is fully data redundant.

Important: During the online replication process, Greenplum Database should be in a quiescent state, workloads and other queries should not be running.

By default, the utility will prompt you for the file system location(s) where it will create the mirror segment data directories. If you do not want to be prompted, you can pass in a file containing the file system locations using the -m option.

The mirror locations and ports must be different than your primary segment data locations and ports.

The utility creates a unique data directory for each mirror segment instance in the specified location using the predefined naming convention. There must be the same number of file system locations declared for mirror segment instances as for primary segment instances. It is OK to specify the same directory name multiple times if you want your mirror data directories created in the same location, or you can enter a different data location for each mirror. Enter the absolute path. For example:

Enter mirror segment data directory location 1 of 2 > /gpdb/mirror
Enter mirror segment data directory location 2 of 2 > /gpdb/mirror

OR

Enter mirror segment data directory location 1 of 2 > /gpdb/m1
Enter mirror segment data directory location 2 of 2 > /gpdb/m2

Alternatively, you can run the gpaddmirrors utility and supply a detailed configuration file using the -i option. This is useful if you want your mirror segments on a completely different set of hosts than your primary segments. The format of the mirror configuration file is:

mirror<row_id>=<contentID>:<address>:<port>:<data_dir>

Where row_id is the row in the file, contentID is the segment instance content ID, address is the host name or IP address of the segment host, port is the communication port, and data_dir is the segment instance data directory.

For example:
mirror0=0:sdw1-1:60000:/gpdata/mir1/gp0
mirror1=1:sdw1-1:60001:/gpdata/mir2/gp1

The gp_segment_configuration system catalog table can help you determine your current primary segment configuration so that you can plan your mirror segment configuration. For example, run the following query:

=# SELECT dbid, content, address as host_address, port, datadir 
   FROM gp_segment_configuration
   ORDER BY dbid;

If creating your mirrors on alternate mirror hosts, the new mirror segment hosts must be pre-installed with the Greenplum Database software and configured exactly the same as the existing primary segment hosts.

You must make sure that the user who runs gpaddmirrors (the gpadmin user) has permissions to write to the data directory locations specified. You may want to create these directories on the segment hosts and chown them to the appropriate user before running gpaddmirrors.

Note: This utility uses secure shell (SSH) connections between systems to perform its tasks. In large Greenplum Database deployments, cloud deployments, or deployments with a large number of segments per host, this utility may exceed the host's maximum threshold for unauthenticated connections. Consider updating the SSH MaxStartups configuration parameter to increase this threshold. For more information about SSH configuration options, refer to the SSH documentation for your Linux distribution.

Options

-a (do not prompt)
Run in quiet mode - do not prompt for information. Must supply a configuration file with either -m or -i if this option is used.
-B parallel_processes
The number of mirror setup processes to start in parallel. If not specified, the utility will start up to 10 parallel processes depending on how many mirror segment instances it needs to set up.
-d master_data_directory
The master data directory. If not specified, the value set for $MASTER_DATA_DIRECTORY will be used.
-i mirror_config_file
A configuration file containing one line for each mirror segment you want to create. You must have one mirror segment listed for each primary segment in the system. The format of this file is as follows (as per attributes in the gp_segment_configuration catalog table):
mirror<row_id>=<contentID>:<address>:<port>:<data_dir>

Where row_id is the row in the file, contentID is the segment instance content ID, address is the host name or IP address of the segment host, port is the communication port, and data_dir is the segment instance data directory.

-l logfile_directory
The directory to write the log file. Defaults to ~/gpAdminLogs.
-m datadir_config_file
A configuration file containing a list of file system locations where the mirror data directories will be created. If not supplied, the utility prompts you for locations. Each line in the file specifies a mirror data directory location. For example:
/gpdata/m1
/gpdata/m2
/gpdata/m3
/gpdata/m4
-o output_sample_mirror_config
If you are not sure how to lay out the mirror configuration file used by the -i option, you can run gpaddmirrors with this option to generate a sample mirror configuration file based on your primary segment configuration. The utility will prompt you for your mirror segment data directory locations (unless you provide these in a file using -m). You can then edit this file to change the host names to alternate mirror hosts if necessary.
-p port_offset
Optional. This number is used to calculate the database ports used for mirror segments. The default offset is 1000. Mirror port assignments are calculated as follows:
primary port + offset = mirror database port
For example, if a primary segment has port 50001, then its mirror will use a database port of 51001, by default.
-s (spread mirrors)
Spreads the mirror segments across the available hosts. The default is to group a set of mirror segments together on an alternate host from their primary segment set. Mirror spreading will place each mirror on a different host within the Greenplum Database array. Spreading is only allowed if there is a sufficient number of hosts in the array (number of hosts is greater than the number of segment instances per host).
-v (verbose)
Sets logging output to verbose.
--version (show utility version)
Displays the version of this utility.
-? (help)
Displays the online help.

Examples

Add mirroring to an existing Greenplum Database system using the same set of hosts as your primary data. Calculate the mirror database ports by adding 100 to the current primary segment port numbers:

$ gpaddmirrors -p 100

Add mirroring to an existing Greenplum Database system using a different set of hosts from your primary data:

$ gpaddmirrors -i mirror_config_file

Where mirror_config_file looks something like this:

mirror0=0:sdw1-1:52001:/gpdata/mir1/gp0
mirror1=1:sdw1-2:52002:/gpdata/mir2/gp1
mirror2=2:sdw2-1:52001:/gpdata/mir1/gp2
mirror3=3:sdw2-2:52002:/gpdata/mir2/gp3

Generate a sample mirror configuration file with the -o option to use with gpaddmirrors -i:

$ gpaddmirrors -o /home/gpadmin/sample_mirror_config