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gpcheckperf

Verifies the baseline hardware performance of the specified hosts.

Synopsis

gpcheckperf -d <test_directory> [-d <test_directory> ...]
    { -f <hostfile_gpcheckperf> | -h <hostname> [ -h <hostname> ... ] }
    [ -r ds ]
    [ -B <block_size> ]
    [ -S <file_size> ]
    [ --buffer-size <buffer_size> ]
    [ -D ]
    [ -v | -V ]

gpcheckperf -d <temp_directory>
    { -f <hostfile_gpchecknet> | -h <hostname> [ -h <hostname> ... ] }
    [ -r n | N | M [ --duration <time> ] [ --netperf ] ]
    [ -D ]
    [ -v | -V ]

gpcheckperf -?

gpcheckperf --version

Description

The gpcheckperf utility starts a session on the specified hosts and runs the following performance tests:

  • Disk I/O test (dd test) — to test the sequential throughput performance of a logical disk or file system, the utility uses the dd command, which is a standard Unix utility. It times how long it takes to write and read a large file to and from disk and calculates your disk I/O performance in megabytes (MB) per second. By default, the file size that is used for the test is calculated at two times the total random access memory (RAM) on the host. This ensures that the test is truly testing disk I/O and not using the memory cache.

  • Memory bandwidth test (stream) — to test memory bandwidth, the utility uses the STREAM benchmark program to measure sustainable memory bandwidth (in MB/s). This tests that your system is not limited in performance by the memory bandwidth of the system in relation to the computational performance of the CPU. In applications where the data set is large (as in Greengage DB), low memory bandwidth is a major performance issue. If memory bandwidth is significantly lower than the theoretical bandwidth of the CPU, then it can cause the CPU to spend significant amounts of time waiting for data to arrive from system memory.

  • Network performance test (gpnetbench) — to test network performance (and thereby the performance of the Greengage DB interconnect), the utility runs a network benchmark program that transfers a 5 second stream of data from the current host to each remote host included in the test. The data is transferred in parallel to each remote host and the minimum, maximum, average and median network transfer rates are reported in megabytes (MB) per second. If the summary transfer rate is slower than expected (less than 100 MB/s), you can run the network test serially using the -r n option to obtain per-host results. To run a full-matrix bandwidth test, you can specify -r M which will cause every host to send and receive data from every other host specified. This test is best used to validate if the switch fabric can tolerate a full-matrix workload.

To specify the hosts to test, use the -f option to specify a file containing a list of host names, or use the -h option to name single host names on the command-line. If running the network performance test, all entries in the host file must be for network interfaces within the same subnet. If your segment hosts have multiple network interfaces configured on different subnets, run the network test once for each subnet.

You must also specify at least one test directory (with -d). The user who runs gpcheckperf must have write access to the specified test directories on all remote hosts. For the disk I/O test, the test directories should correspond to your segment data directories (primary and/or mirrors). For the memory bandwidth and network tests, a temporary directory is required for the test program files.

Before using gpcheckperf, you must have a trusted host setup between the hosts involved in the performance test. You can use the gpssh-exkeys utility to update the known host files and exchange public keys between hosts if you have not done so already. Note that gpcheckperf calls to gpssh and gpscp, so these Greengage DB utilities must also be in your PATH.

Options

-B <block_size>

Specify the block size (in KB or MB) to use for disk I/O test. The default is 32 KB, which is the same as the Greengage DB page size. The maximum block size is 1 MB.

--buffer-size <buffer_size>

Specify the size of the send buffer in kilobytes. Default size is 32 kilobytes.

-d <test_directory>

For the disk I/O test, specify the file system directory locations to test. You must have write access to the test directory on all hosts involved in the performance test. You can use the -d option multiple times to specify multiple test directories (for example, to test disk I/O of your primary and mirror data directories).

-d <temp_directory>

For the network and stream tests, specify a single directory where the test program files will be copied for the duration of the test. You must have write access to this directory on all hosts involved in the test.

-D

Report performance results for each host for the disk I/O tests. The default is to report results for just the hosts with the minimum and maximum performance, as well as the total and average performance of all hosts.

--duration <time>

Specify the duration of the network test in seconds (s), minutes (m), hours (h), or days (d). The default is 15 seconds.

-f <hostfile_gpcheckperf>

For the disk I/O and stream tests, specify the name of a file that contains one host name per host that will participate in the performance test. The host name is required, and you can optionally specify an alternate user name and/or SSH port number per host. The syntax of the host file is one host per line as follows:

[<username>@]<hostname>[:<ssh_port>]
-f <hostfile_gpchecknet>

For the network performance test, all entries in the host file must be for host addresses within the same subnet. If your segment hosts have multiple network interfaces configured on different subnets, run the network test once for each subnet. For example (a host file containing segment host address names for interconnect subnet 1):

sdw1-1
sdw2-1
sdw3-1
-h <hostname>

Specify a single host name (or host address) that will participate in the performance test. You can use the -h option multiple times to specify multiple host names.

--netperf

Specify that the netperf binary should be used to perform the network test instead of the Greengage DB network test. To use this option, you must download netperf and install it into $GPHOME/bin/lib on all Greengage DB hosts (master and segments).

-r ds{n|N|M}

Specify which performance tests to run. The default is dsn:

  • Disk I/O test (d).

  • Stream test (s).

  • Network performance test in sequential (n), parallel (N), or full-matrix (M) mode. The optional --duration option specifies how long (in seconds) to run the network test. To use the parallel (N) mode, you must run the test on an even number of hosts.

    If you would rather use netperf instead of the Greengage DB network test, you can download it and install it into $GPHOME/bin/lib on all Greengage DB hosts (master and segments). You would then specify the optional --netperf option to use the netperf binary instead of the default gpnetbench utilities.

-S <file_size>

Specify the total file size to be used for the disk I/O test for all directories specified with -d. file_size should equal two times total RAM on the host. If not specified, the default is calculated at two times the total RAM on the host where gpcheckperf is run. This ensures that the test is truly testing disk I/O and not using the memory cache. You can specify sizing in KB, MB, or GB.

-v

Show progress and status messages of the performance tests as they are run.

-V

Show all output messages generated by this utility.

--version

Display the version of this utility.

-?

Display help.

Examples

Run the disk I/O and memory bandwidth tests on all the hosts in the file hostfile_gpcheckperf using the test directory of /data1 and /data2:

$ gpcheckperf -f hostfile_gpcheckperf -d /data1 -d /data2 -r ds

Run only the disk I/O test on the hosts named sdw1 and sdw2 using the test directory of /data1. Show individual host results and run in verbose mode:

$ gpcheckperf -h sdw1 -h sdw2 -d /data1 -r d -D -v

Run the parallel network test using the test directory of /tmp, where hostfile_gpchecknet_ic* specifies all network interface host address names within the same interconnect subnet:

$ gpcheckperf -f hostfile_gpchecknet_ic1 -r N -d /tmp
$ gpcheckperf -f hostfile_gpchecknet_ic2 -r N -d /tmp

Run the same test as above, but use netperf instead of the Greengage DB network test:

$ gpcheckperf -f hostfile_gpchecknet_ic1 -r N --netperf -d /tmp
$ gpcheckperf -f hostfile_gpchecknet_ic2 -r N --netperf -d /tmp

See also

Previous
gpcheckcat
Next
gpconfig