The Raritan Dominion PX series of Power Distribution Units (PDUs), available from Dueltek Computer Products , keep track of power consumption and record temperature and humidity data from sensors placed among the servers.
When combined with an un-interruptible power supply, the Raritan Dominion PX series will keep the servers safe and happy.
People always ask what their computers can do for us, but do they ever stop and think about what they can do for them? Being kind to the equipment will result in better reliability and a reduced likelihood of failure.
A quick look at the specifications for the equipment will show acceptable temperature and humidity levels. Hot equipment is equipment heading for failure. In server racks, heat from each machine can contribute to the discomfort of neighbouring devices.
Dueltek Computer Products mainly assessed the ease of use for this device, but in addition they checked that temperature and power consumption readings were accurate.
Usability includes initial set-up and configuration issues as well as the ease with which data-logs can be accessed. Dueltek Computer Products compared the power readings against two power meters and the temperature against an optical thermometer. Dueltek Computer Products also assessed documentation quality and the level of expertise required to use the device.
Design and features
The Dominion PX series are Power Distribution Units (PDUs), which come in zero Rack Units (RU), 1U and 2U models with eight to 20 outlets.
Dueltek Computer Products reviewed, the PX8 model, which was a 1RU model bearing eight power outlets. The power inlet has a fixed cord with screw-in plug.
Each rear-mounted outlet nestles beside a tricolour status LED and the front of the device bears three RJ-45 sockets for connection to environment sensors, telnet and a LAN.
Set up is not a major task, but one will probably want to use a network sniffer if using DHCP. The device has a default IP address, but will use DHCP where possible.
The alternative is to use telnet to get in and assign the address through com-port, which is a legacy technology and a painful experience.
Once the user has it all plugged in and managed to locate the network address, it is a simple matter of logging into the management interface through a Web browser.
Critical power or environmental changes as well as log-ins and other administrative events are recorded in an event log. It is possible to accurately define what events are recorded and how the system should respond.
For example, one can specify what humidity and temperature levels are unacceptable (both upper and lower limits) and these events may simply be logged or a message may be sent to an administrator through e-mail.
In critical cases the user may set the system to automatically shut-down power to certain devices for an extended period, or momentarily to force a reboot.
If necessary the user can limit the amount of power to particular outlets — thus ensuring other critical systems do not go without. The user can also cycle power between supplies where devices have multiple power supplies.
Using PX trend analysis software it is possible to hunt down servers, which are constantly using little power (indicating that they may not be being used) and may discover that power distribution could be better balanced between adjacent racks.
Other software with SNMP can be used to access data from the device for more advanced reporting. Also, the Dominion is compatible with the IPMI protocol allowing for detailed interrogation and commands to be sent without manual intervention; Free OpenSource client software (for Linux) can be downloaded from Sourceforge.
The Dominion has its own firewall to limit access to specified IP ranges. Access is password protected and multiple user accounts with differing permission levels can be created. It is also important to note that rules can be employed to enforce strong passwords.
Further security can be applied by enforcing a HTTPS connection. Identity verification can employ Digital certificates, LDAP and RADIUS protocols, and when using multiple units are required to assess the server banks, the devices can be networked to simplify management and data collection.
Basic management tasks can be achieved with a minimum of expertise. If people just want to know when conditions go critical, they can just plug everything in, set the desired alert levels for each user, give the machine e-mail privileges and wait for it to inform when trouble strikes.
If people want detailed energy and environmental logs they will need staff familiar with server management to set up something like OpenIPMI.
Temperature and power usage readings appear to be accurate. Raritan only claim 5% accuracy on power levels and Dueltek Computer Products’ readings were certainly within 5% of those made by the Dominion PX8.
These machines will be welcome additions to any server rack — particularly in situations where there is reason to suspect trouble (e.g., tropical environments, dense server packing or unreliable supply power).