<!--#set var="TITLE" value="CTDB Testing" --> <!--#include virtual="header.html" --> <H2 align="center">Starting and testing CTDB</h2> The CTDB log is in /var/log/log.ctdb so look in this file if something did not start correctly.<p> You can ensure that ctdb is running on all nodes using <pre> onnode all service ctdb start </pre> Verify that the CTDB daemon started properly. There should normally be at least 2 processes started for CTDB, one for the main daemon and one for the recovery daemon. <pre> onnode all pidof ctdbd </pre> Once all CTDB nodes have started, verify that they are correctly talking to each other.<p> There should be one TCP connection from the private ip address on each node to TCP port 4379 on each of the other nodes in the cluster. <pre> onnode all netstat -tn | grep 4379 </pre> <h2>Automatically restarting CTDB</h2> If you wish to cope with software faults in ctdb, or want ctdb to automatically restart when an administration kills it, then you may wish to add a cron entry for root like this: <pre> * * * * * /etc/init.d/ctdb cron > /dev/null 2>&1 </pre> <h2>Testing CTDB</h2> Once your cluster is up and running, you may wish to know how to test that it is functioning correctly. The following tests may help with that <h3>The ctdb tool</h3> The ctdb package comes with a utility called ctdb that can be used to view the behaviour of the ctdb cluster.<p> If you run it with no options it will provide some terse usage information. The most commonly used commands are: <pre> ctdb status ctdb ip ctdb ping </pre> <h3>ctdb status</h3> The status command provides basic information about the cluster and the status of the nodes. when you run it you will get some output like: <pre> <strong>Number of nodes:4 vnn:0 10.1.1.1 OK (THIS NODE) vnn:1 10.1.1.2 OK vnn:2 10.1.1.3 OK vnn:3 10.1.1.4 OK</strong> Generation:1362079228 Size:4 hash:0 lmaster:0 hash:1 lmaster:1 hash:2 lmaster:2 hash:3 lmaster:3 <strong>Recovery mode:NORMAL (0)</strong> Recovery master:0 </pre> The important parts are in bold. This tells us that all 4 nodes are in a healthy state.<p> It also tells us that recovery mode is normal, which means that the cluster has finished a recovery and is running in a normal fully operational state.<p> Recovery state will briefly change to "RECOVERY" when there ahs been a node failure or something is wrong with the cluster.<p> If the cluster remains in RECOVERY state for very long (many seconds) there might be something wrong with the configuration. See /var/log/log.ctdb. <h3>ctdb ip</h3> This command prints the current status of the public ip addresses and which physical node is currently serving that ip. <pre> Number of nodes:4 192.168.1.1 0 192.168.1.2 1 192.168.2.1 2 192.168.2.1 3 </pre> <h3>ctdb ping</h3> this command tries to "ping" each of the CTDB daemons in the cluster. <pre> ctdb ping -n all response from 0 time=0.000050 sec (13 clients) response from 1 time=0.000154 sec (27 clients) response from 2 time=0.000114 sec (17 clients) response from 3 time=0.000115 sec (59 clients) </pre> <!--#include virtual="footer.html" -->