================== Cluster Validation ================== Before installing MapR Hadoop it is invaluable to validate the hardware and software that MapR will be dependent on. Doing so will verify that items like disks and DIMMs are performing as expected and with a known benchmark metric. Doing so will also verify that many of the basic OS configurations and packages are in the required state and that state is also recorded in the output log. Please use the steps below to test CPU/RAM, disk, and networking performance as well as to verify that your cluster meets MapR installation requirements. Pre-install tests should be run before installing MapR. Post-install tests should be run after installing the MapR software and configuring a cluster. Post-install tests help assure that the cluster is in good working order and ready to hand over to your production team. Install clush (rpm provided, also available via EPEL) on a machine with passwordless ssh to all other cluster nodes. If using a non-root account, then non-root account should have passwordless sudo rights configured in /etc/sudoers. Update the file /etc/clustershell/groups to include an entry for "all" matching a pattern or patterns of host names. For example; "all: node[0-10]" Verify clush works correctly by running "clush -a date". Compare results with "clush -ab date". Download and extract the cluster-validation package with a command like this: curl -LO 'https://github.com/jbenninghoff/cluster-validation/archive/master.zip' Extract with unzip master.zip and move the pre-install and post-install folder directly under /root for simplicity. Copy the /root/pre-install folder to all nodes in the cluster. The clust commmand, properly configured, simplifies this : clush -a --copy /root/pre-install clush -Ba ls /root/pre-install # confirm that all nodes have the utilties Step 1 : Gather Base Audit Information -------------------------------------- Use cluster-audit.sh to verify that you have met the MapR installation requirements. Run: /root/pre-install/cluster-audit.sh | tee cluster-audit.log on the node where clush has been installed and configured to access all cluster nodes. Examine the log for inconsistency among any nodes. Do not proceed until all inconsistencies have been resolved and all requirements such as missing rpms, java version, etc have been met. Please send the output of the cluster-audit.log back to us. NOTE: cluster-audit.sh is designed for physical servers. Virtual Instances in cloud environments (eg Amazon, Google, or OpenStack) may generate confusing responses to some specific commands (eg dmidecode). In most cases, these anomolies are irrelevant. Step 2 : Evaluate Network Interconnect Bandwidth ------------------------------------------------ Use the RPC test to validate network bandwidth. This will take about two minutes or so to run and produce output so please be patient. Update the half1 and half2 arrays in the network-test.sh script to include the first and second half of the IP addresses of your cluster nodes. Delete the exit command also. Run: /root/pre-install/network-test.sh | tee network-test.log on the node where clush has been installed and configured. Expect about 90% of peak bandwidth for either 1GbE or 10GbE networks: 1 GbE ==> ~115 MB/sec 10 GbE ==> ~1100 MB/sec Step 3 : Evaluate Raw Memory Performance ---------------------------------------- Use the stream59 utility to test memory performance. This test will take about a minute or so to run. It can be executed in parallel on all the cluster nodes with the command : clush -Ba '/root/pre-install/memory-test.sh | grep ^Triad' | tee memory-test.log Memory bandwidth is determined by speed of DIMMs, number of memory channels and to a lesser degree by CPU frequency. Current generation Xeon based servers with eight or more 1600MHz DIMMs can deliver 70-80GB/sec Triad results. Previous generation Xeon cpus (Westmere) can deliver ~40GB/sec Triad results. Step 4 : Evaluate Raw Disk Performance -------------------------------------- Use the iozone utility to test disk performance. This process is destructive to disks that are tested, so make sure that sure that you have not installed MapR nor have any needed data on those spindles. The script as shipped will ONLY list out the disks to be tested. You MUST edit the script once you have verified that the list of spindles to test is correct. The test can be run in parallel on all nodes with: clush -ab /root/pre-install/disk-test.sh Current generation (2012+) 7200 rpm SATA drives can produce 100-145 MB/sec sequential read and write performance. For larger numbers of disks there is a summIOzone.sh script that can help provide a summary of disk-test.sh output. Complete Pre-Installation Checks -------------------------------- When all subsystem tests have passed and met expectations, there may be an example install script in the pre-install folder that can be modified and used for a scripted install. Otherwise, follow the instructions from the mapr.com web site for cluster installation. Post install tests are in the post-install folder. The primary tests are RWSpeedTest and TeraSort. Scripts to run each are provided in the folder. Read the scripts for additional info. A script to create a benchmarks volume (mkBMvol.sh) is provided. Additionally, runTeraGen.sh is provided to to generate the terabyte of data necessary for the TeraSort benchmark. Be sure to create the benchmarks volume before running any of the post install benchmarks. NOTE: The TeraSort benchmark (executed by runTeraSort.sh) will likely require tuning for each specific cluster. Experiment with the -D options as needed. There is also a mapr-audit.sh script which can be run to provide an audit snapshot of the MapR configuration. The script is a useful set of example maprcli commands. There are also example install, upgrade and uninstall scripts. None of those will run without editing, so read the scripts carefully to understand how to edit them with site specific info. /John Benninghoff