Marching Penguins: Monitoring Your HPC Cluster

Getting into Ganglia for a scalable and flexible solution to the problem of cluster monitoring.

As the proud System Administrator a shiny new cluster sits in front of you, a nice set of LINPACK results are complete, and a bunch of jobs running through the queues. Things are good, users are happy, and you can catch up on all those other projects you have pending. Then you get an email: “Why are my jobs slow?” Or a project manager comes by and wants to know if the expensive new hardware is actually being used. Perhaps you are trying to plan for the coming year and need to know the recent usage trends. Monitoring your systems to establish a set of baseline figures and current performance information can help with each of these problems.

The idea of “monitoring” is somewhat overloaded (much like the word “clustering” itself). In High Performance Computing (HPC), most attention is paid to the utilization and performance metrics of compute nodes, rather than focusing on service availability and problem notification. This article will focus on the former, while programs such as Nagios and OpenNMS are excellent at handling the latter.

For the purpose of this article, it is assumed that you have access to a working cluster; a functioning web server with mod_php (including GD support); and are comfortable with basic administration tasks, Apache configuration, and using command line tools. The commands below were run on CentOS 5 and Gentoo systems, but the general concepts should apply to all common Linux distributions (and most other UNIX-like operating systems as well).


Monitoring itself can be broken down into two broad parts. The first is actually determining which metrics are needed and then collecting that data from the hosts. Some of the most commonly tracked metrics are CPU usage, memory consumption, network bandwidth, and disk I/O stats. These provide different indications of how well a system is performing, and may indicate where there are potential problems or performance bottlenecks. Once the data have actually been acquired, the second task is presenting the information in a meaningful way for analysis.

Linux provides a large number of utilities to access data about the system. A few common tools are vmstat, iostat, and netstat, although there are many others. These programs are typically geared toward non-interactive use—an important consideration for continuously monitoring systems. Programs that are interactive in nature (like top) will not work well unless they have some form of batch mode that is easily parsed. Some programs, such as sar and atop, have data collection modes and can produce detailed reports on a wide range of metrics. When all else fails, it is possible to pull numbers directly from the /proc or /sys filesystems, although you may need to manipulate the raw data to get usable information. For example, the various “CPU %” values are actually calculated from values found in /proc/stat.

Almost all metrics can be reduced to a number, or collection of numbers, marked with a timestamp; these are then stored for later retrieval. Storage formats can range from the simple (a plain text file) to the complicated (a set of fully normalized SQL tables). The RRD format used by rrdtool was designed to store metric data, and it is very well suited for this task. Ganglia (more below) makes extensive use of RRD files for its data storage.

For basic monitoring, vmstat is a natural place to start. It can tell us a great deal about the system, and it reports at regular intervals. The commands in Listing One tell vmstat to report every 5 seconds and print the column header line only once (normally, it displays the header frequently enough to have it displayed once per terminal). The first three lines are unnecessary for our current purpose since lines 1 and 2 are column headers, and line 3 reports average values since the last system reboot. Unfortunately, vmstat will not show load averages, but we can work around this with help from other programs.

To do this, we tell awk to print a timestamp for each line, and also grab the contents of /proc/loadavg (which stores the current load average). Finally, the output is sent to the tee command so that the output is displayed on STDOUT and saved to the vmstat.dat file. Normally, a simple file redirect is sufficient to just store the data. For each of these programs, please check their respective man pages for details on usage, command syntax, and output format.

$ vmstat -n 5 | awk '(NR>3){getline load < "/proc/loadavg"; print systime(), $0, load }' | tee vmstat.dat
1196738925 0 1  188 138820 254824 674948  0  0   2  0 3470 9566 35 11 54 0 0.46 0.38 0.52 1/140 31493
1196738935 1 0  188 123972 263420 674948  0  0  860  0 3648 9876  6 12 0 82 0.63 0.41 0.53 2/140 31493
1196738945 0 1  188 99296 273700 674976  0  0 1029  0 3708 10016 6 13 0 82 0.68 0.43 0.54 1/140 31493
1196738955 1 1  188 89716 281340 674976  0  0  764  0 3654 9921  6 10 0 84 0.73 0.45 0.54 1/140 31493

The example in Listing One stores the data in a single ASCII flat file. The advantage to this format is simplicity: the data are immediately available, and no special tools are needed to extract it. The disadvantages are just about everything else. Storing numbers as raw text is not an efficient use of disk space, and for very large files, reading and processing the data can take significant amounts of time. No metadata is kept, and the files need to be managed in such a way that it is known what data they represent. For example, in the output file above, unless it is known that data came from vmstat, we have no way to be sure what it represents. For very simple (and perhaps temporary) monitoring, flat files work fine. For serious data collection, a more robust solution (such as using RRD files or a true database) is worth considering.


The amount of data collected in even a small cluster can quickly become unwieldy, and making sense of it is the other half of “monitoring” (and indeed, the whole point!). As the saying goes, “a picture is worth a thousand words.”

Taking the data from vmstat, we can send it to gnuplot to get an idea of system performance during this period of time. The vmstat and awk commands above produced a file with twenty-one different metrics, plus a timestamp; it becomes obvious why managing many different metrics can be a challenge. In the present case, we want columns 1, 14, 15, and 18, which refer to the timestamp, user CPU%, system CPU%, and 1-minute load average, respectively. See the sidebar on gnuplot at the end of the article for details on plotting the data.

Figure One: Plot of data from vmstat and /proc/loadavg

As the plot in Figure One shows, the system was fairly busy at the time: several virtual machines were running, and a number of large software packages were being compiled. The high level of system CPU time is due mainly to heavy disk I/O and overhead from the virtual machines. Notice that the load numbers nicely track CPU usage.


As is frequently the case in the open source world, someone else has already written software to solve the problem, and monitoring clusters is no exception.

Ganglia consists of several components designed specifically for the different aspects of monitoring, collecting, and displaying metrics from HPC systems in an efficient and scalable way. It was originally written by Matt Massie at the University of California, Berkeley (unsurprisingly, Ganglia was released under a BSD license), and is actively maintained by a small group of developers. Ganglia is used by commercial, educational, government, and non-profit organizations across the world to monitor some of the largest clusters currently in operation. A partial, but still impressive, list of organizations using Ganglia can be found on the Ganglia homepage. The current stable release is ganglia-3.1.0. This new release has a number of improvements over the previous 3.0.x series, including a new modular interface for adding metrics directly to gmond (with C and Python bindings), the addition of several new core metrics, and a number of display improvements. While the screenshots below were taken using version 3.0.5, the setting up a new Ganglia 3.1.0 installation is essentially the same.

Installing Ganglia is straightforward, and most recent distributions provide packages; some RPMs are also provided for download from the SourceForge website. However, if packages are not available or out of date, tarballs can be found on the Ganglia homepage. The web frontend will needs Apache, mod_php, and PHP must have GD support. Otherwise, the common mantra of “configure; make; make install” should work fine. To install the web frontend, simply copy the “web” directory into the Apache document root and rename it to “ganglia”. See Listing Two below.

$ tar xzf ganglia-3.0.5.tar.gz
$ cd ganglia-3.0.5
$ ./configure --with-gmetad
$ make
$ sudo make install
$ sudo cp -r web html_docroot/ganglia

As shown in Figure Two, there are four main parts to Ganglia

  • gmond is responsible for collecting a basic set of core metrics (CPU usage, basic network and memory stats, etc) about the local machine. The gmond daemons send data out over multicast (by default) or unicast to other gmond daemons within the cluster. This way, each daemon can track the global state of the cluster at any time, and any one of them can provide a complete report to gmetad.
  • The gmetad daemon is the heart of the system. It collects metrics from one or more gmond daemons and stores them in RRD files for later retrieval. gmetad can also poll other gmetad instances for summary information on other clusters. This is known as “federation”, and is useful for creating summary views of discrete, but related, clusters.
  • A web frontend built on PHP is used to actually display the data. When each page is loaded, the PHP scripts will request relevant data from gmetad in order to generate the page requested. There are a number of pre-made reports that provide very useful views into the workings of the cluster as a whole, and custom reports can be written. The web frontend does not need to run on the same computer as gmetad, but it does make configuration simpler.
  • For metrics not directly supported by gmond, Ganglia includes the command line program gmetric to track additional metrics. These are reported to gmond, which passes them to gmetad along with the built-in statistics. New in the 3.1.0 release is the ability to extend gmond directly by writing modules in C or Python.

Figure Two: Ganglia Overview

Each compute node will need a gmond process to collect data, and the master node (or adminstration node) will need to run gmetad. Gmond listens for incoming requests from gmetad on TCP port 8649 and sends and receives multicast traffic on address, port 8649. The gmetad daemon listens on TCP ports 8651 and 8652. If there are problems using multicast, make sure that the IP routing table is configured to handle multicast traffic correctly.

Just about anything that can be quantified can be passed to gmetric. For example, to count the number of unique users logged into a system and feed that into Ganglia, the shell script in Listing Three will work.

USERS=`who | awk '{print $1}' | sort -u | wc -l`
gmetric -n users_loggedin -v $USERS -t uint8 -u Users

The command line options -n (name of metric), -v (value of the metric) and -t (metric datatype) are required for each call to gmetric. The -u option indicates the units for this metric; its use is optional, but recommended.

For devices that cannot run gmond directly, it is possible to use gmetric to send data on their behalf. This ability to “spoof” reports from other hosts permits Ganglia to monitor data from embedded systems, proprietary hardware, and other devices. For example, many uninterruptible power supplies (UPS) have internal temperature sensors and support network management cards with built-in SNMP agents. Covering SNMP is well beyond the scope of this article, although there are a number of excellent resources online (see the References sidebar). Assuming you have snmpget from the Net-SNMP project, temperature data from the UPS can be fed into Ganglia using the script in Listing Four below:

# Name and IP address of the UPS, and OID.
# The OID is specific to APC hardware,
# but other vendors provide similar support.
TEMPERATURE=`snmpget -O qv -c public -v 1 $IP $OID`
gmetric -n temperature -v $TEMPERATURE -t int8 -u 'deg C' -S $IP:$UPS

This script should be suitable to call from crond on a regular basis. Ganglia expects metrics to be updated once every 60 seconds, but this can be adjusted if needed, depending on the expected behavior.

Notice that the datatype used in this example is “int8″ instead of “uint8″ from the previous example. This indicates that Ganglia, via rrdtool, should use a signed 8-bit integer for storing the temperature data, as opposed to an unsigned 8-bit integer for logged-in users. Temperature can be negative–although it hopefully never gets that cold in the datacenter. The number of users will never be negative, so an unsigned integer will work. This script can easily be expanded to poll for other information, such as the UPS’ outgoing amperage or incoming voltage. Integer and floating point datatypes up to 32 bits long are also available.

For this article, I created a small 4 node cluster using virtual machines. There is one head node and three compute nodes, each with one single-core CPU. While no powerhouse, it works wonderfully for demonstrations. Each of the compute nodes is running gmond, and the head node runs gmond, gmetad and the web frontend.

The default configuration files for gmond (“/etc/gmond.conf”) and gmetad (“/etc/gmetad.conf”) should work without modification. However, for a production install of Ganglia, change the data_source setting in “gmetad.conf” (See the comments in the file, if you are running a gmond on the head node, then localhost will work.) and the cluster { name = "unspecified" } entry in “gmond.conf&quot to match. Also look at the various access control measures supported by both daemons, especially if using the spoofing feature.

The screenshot in Figure Three shows the Ganglia installation running on the test cluster. Ganglia displays a great deal of information in a fairly compact space. The top of the webpage provides a general overview of the cluster plus CPU, memory, and network statistics. When a host is offline, that is indicated as well.

Figure Three: Ganglia in Action

The bottom section of the webpage shows per-node statistics, with one graph per system. The default settings show the 1-minute load. The nodes are sorted in descending order, so busy nodes are listed first. This choice can be changed via the “metric” drop-down field displayed at the very top of the page. The coloring of the chart is always based on the current 1-minute load, divided by the number of CPUs. Thus, a load of 1.02 on a single-CPU box is colored red, whereas a load of 2.06 on a box with 8 cores is colored light green. A detailed page on a specific host is available by clicking on the per-node chart for that host or by choosing the node specifically from the “Choose a Node” drop-down menu, also at the top of the page.

The timescale is the same for all of the charts, making it easy to correlate different metrics. For example, at about 01:10, node2 went offline. The number of available CPUs and amount of memory reported by Ganglia both dropped to reflect this. Also in the load report, there was a drop in the 1-minute load from about 3.0 to about 2.0. This makes sense, since the value displayed is the sum of all 1-minute loads across the cluster, and each of the two nodes reports a load slightly less than 1.0. The other reports will show similar changes when a node goes offline, although in this test the effects are subtle.

For HPC systems, monitoring performance metrics is an important part of making sure that clusters are running well. There are many different ways of managing and displaying the data, and the specific one chosen will depend on many different factors. Ganglia provides a scalable and flexible solution to the problem and is well worth considering. It is also possible to write a custom solution using command line tools and custom scripts. While perhaps not as quick a solution to deploy, writing such a program will teach you a great deal about your system, and there is much to be said for learning something new.

Sidebar: Gnuplot

Gnuplot is a surprisingly powerful program, and over the course of many years, I have kept coming back to it. I
have frequently done data analysis in other programs with built-in graphing functions (including OpenOffice Calc and Microsoft Excel), but often export the data to gnuplot for analysis and presentation.

Below are the commands to plot the data from vmstat and /proc/loadavg. The various set lines
define the chart parameters and tell gnuplot how to deal with the data. The plot and replot statements actually draw lines on the chart.

These lines tells the program to pull data from the “vmstat.dat” file, using column 1 as the x-axis value (which you will recall is
the timestamp), and columns 14, 15 and 18 for the y values then connect them with lines (gnuplot has a very wide range of plotting styles). For the two replot lines, there are also several additional parameters to adjust the line
color and appearance.

Consult the Gnuplot documentation for more complete explanations and examples.

set key inside left top
set xdata time
set timefmt "%s"
set format x "%H:%M"
set xlabel "Time"
set ylabel "CPU %"
set ytics nomirror
set y2label "Load average"
set y2range [0:]
set y2tics 1
set my2tics 0.5
plot 'vmstat.dat' using 1:14 \
  title 'user cpu%' with lines
replot 'vmstat.dat' using 1:15 \
  title 'sys cpu%' with lines \
  linecolor 3
replot 'vmstat.dat' using 1:18 title 'load 1' \
  with lines linecolor 7 linewidth 2 \
  axes x1y2 smooth bezier


Comments on "Marching Penguins: Monitoring Your HPC Cluster"


does ganglia notify if one node goes down in cluster?


Ganglia handles monitoring, but not notification. Several people have written small “glue” programs to link Ganglia and Nagios, and this comes up on the mailing list periodically (search for “nagios”, “alterting”, and “XML Parser for Gmetad”). http://www.mail-archive.com/ganglia-general@lists.sourceforge.net/

Additionally, the company GroundWork Open Source has a product that specifically ties together Ganglia, Nagios, and several other programs into a single integrated system that supports both monitoring and notification. See http://www.groundworkopensource.com/community/downloads/plugins-download.html for details.


Hey, thanks for the blog.Really thank you! Awesome.


I have learn a few just right stuff here. Certainly worth bookmarking for revisiting. I surprise how much effort you set to create this sort of excellent informative site.


Hello Web Admin, I noticed that your On-Page SEO is is missing a few factors, for one you do not use all three H tags in your post, also I notice that you are not using bold or italics properly in your SEO optimization. On-Page SEO means more now than ever since the new Google update: Panda. No longer are backlinks and simply pinging or sending out a RSS feed the key to getting Google PageRank or Alexa Rankings, You now NEED On-Page SEO. So what is good On-Page SEO?First your keyword must appear in the title.Then it must appear in the URL.You have to optimize your keyword and make sure that it has a nice keyword density of 3-5% in your article with relevant LSI (Latent Semantic Indexing). Then you should spread all H1,H2,H3 tags in your article.Your Keyword should appear in your first paragraph and in the last sentence of the page. You should have relevant usage of Bold and italics of your keyword.There should be one internal link to a page on your blog and you should have one image with an alt tag that has your keyword….wait there’s even more Now what if i told you there was a simple WordPress plugin that does all the On-Page SEO, and automatically for you? That’s right AUTOMATICALLY, just watch this 4minute video for more information at. Seo Plugin


I’??ve read many excellent stuff here. Unquestionably worth bookmarking for revisiting. I surprise how a great deal try you set to create this sort of great informative internet site.


With this fact, the benefits of each product must be addressed in your keywords. Every year, practically a million people crowd into the Times Square area of New York City for one of the world’s largest annual parties. But they better look over their shoulders because Miami is closing the gap.In a sense, January 1st is an odd date because there isn’t anything special about it from an astronomical standpoint. They already have other divas coming back for the Battle Royal including Trish Stratus to many reports.
Cheap Jerseys From China http://www.cheapjerseysforcheapest.com/


YShpLY This is very interesting, You are a very skilled blogger. I have joined your rss feed and look forward to seeking more of your wonderful post. Also, I ave shared your web site in my social networks!


Yes! Finally something about tvv ?ovlar?.

Here is my web blog; ipopcorn movies


An interesting discussion is definitely worth comment. There’s no doubt that that you should write more about this issue, it might not be a taboo matter but generally people do not discuss these topics. To the next! Cheers!!|


Please pay a visit to the sites we follow, like this one particular, because it represents our picks in the web.


Very couple of web-sites that take place to become in depth beneath, from our point of view are undoubtedly very well really worth checking out.


Government people and self proclaimed experts call it a pyramid. This fosters character traits such as responsibility and discipline. As a fun note, make the items to put on silly and fun. She even thinks that her brain isnt in her head. Practice rounds are also beneficial as you can try different clubs for the par threes.
Wholesale NFL Jerseys Cheap http://www.wholesalechinajerseysnfl.us.com/


Founded by Cardinal Wolsey in 1524, Christ Church isthe oldest college in the Oxford University system and serves asOxfords Cathedral. Sorry, the big lie is here. On the other hand, treating others with respect and using positive communication resolve conflicts and create peaceful solutions–a goal everyone should strive for.0390.”People are eating more and wondering why they’re getting fatter,” says Melanie Polk, MMSc, RD, director of Nutrition Education at the AICR.
Cheap NFL Jerseys http://www.nfljerseyschinawholesaler.com/


Note that attacking with the long pimple rubbers is not recommended, as these technique as more advanced, but for blocking and chopping they are fairly easy to use at any level. Technically you need one red and one black rubber on either side of the bat. Open to both dogs and children this familyfriendly bar is also largely handicapped accessible. I have been in furious battle with them for years about this. There are too many easier internet opportunities to compete with it.
Wholesale Jerseys Free Shipping http://www.nfljerseys-supply.us/


However, there is certainly evidence that early detection has made a significant contribution. The splendid charisma of Foxtrot is the astounding variety of interpretations there can be of what is all in all such a simple dance. Even the seven-time champion of the Tour de France, Lance Armstrong, has an extensive fan base for memorabilia and sports collectibles.In spite of the urgings of national well being organizations for girls to have Michael Kors Outlet yearly or biannual mammograms following the age of 40, uncertainty and controversy in regards to the process persists.When it comes to the value of the items you collect, remember that the more famous the star, the more expensive the baseball memorabilia and sports collectible items will be. Spend less and quire a lot more. The particular heat, currently the water pipe really does handy spray producing a surrounding analogy he was quoted saying: “It could be really like when folks would expect to weight loss of raise the temperature of. that would permit to obtain printable coupons.Students of dance are taught how to express their philosophy and emotions through innurable forms of dance such as modern, jazz, indigenous, folk, and ballet. One’s destiny of predominantly let you know machinery, most notably to name consequentially snap a smile the particular “simple electronic camera”, is predicted to take place in later life including “everyday living sturdy vertical structure”, additionally 30 distinct tools.
Cheap Jerseys China http://www.cheapjerseystickets.us.com/


In this article, you’ll be able to learn from the mistakes that others have made, and create an article marketing campaign that will be a success from the start. Discounted tickets on popular nights in New York has proven very difficult as well.. Technically you need one red and one black rubber on either side of the bat. However if people focused more on these top ten golf tips they will improve their game.
Wholesale NFL Jerseys http://www.wholesalejerseysnflchinashop.com/


This association was formed in the year 1920 and then its name was American Professional Football Association.Mammography is definitely an imperfect screening tool. Mercury in deep exaltation with Wednesday in sunrise. You can easily find 2 distinct forms of fundraisers.For a low-cost quarterly mberip, you’ll gain right to use to more than just a list of upcoming dance auditions, dance postings and dance jobs. Even right after biopsy and microscopic exam, it is actually challenging to predict how a tumor will develop. Just after all, for many years girls were informed to complete Michael Kors self examinations of their breasts, but not too long ago that tips was discontinued following a substantial research found it completely ineffective at minimizing the death price from breast most cancers. Sun – mbers of political departnt, civil servants, lawyers, magistrates and the ministers. The study, printed inside the New England Journal of Medication, concludes that 28 to 65 percent of the sharp decrease in breast most cancers fatalities from 1990 to 2000 was on account of mammograms.”Thrive group of buyers of immersive retaining wallThe particular following exhibition is a type of could very well contain 600 live entertainment visitors, are you going to the actual icon as to Sino-Japanese relationship regarding ideas — ibis degree shows.
Cheap NFL Jerseys China Wholesale http://www.cheapchinajerseysnflshop.us.com/


Lines can be long but thegalleries and gardens are well worth the wait.Oxford Hotels & AccommodationAs a university town, Oxford offers lodging running the gamut from bedand breakfast to the most luxurious of accommodations. They swarm you with dishonest arguments as to why they can do this.Respondents to the AICR survey were asked to estimate the standard servings defined by the USDA Food Guide Pyramid for eight different foods, including pasta, green salad, beans, and mashed potatoes. When Major Nesbeth was finally released, he found that he had cut 20 strokes off his golfing average without having touched a golf club in seven years.
Cheap Jerseys http://www.wholesalenfljerseyssupplychina.us.com/


On the other hand, treating others with respect and using positive communication resolve conflicts and create peaceful solutions–a goal everyone should strive for. A bare cell, little food, psychological and physical mistreatment. The distance from the base line approximately with 10, feet of the net can be regarded as no-man’s-ground or. Because the spin coming off the two different rubber is so different, hitting the ball with one side followed by a hit from the other side will produce very different results, leaving your opponent totally confused. The face of racquet voyage along the ground with a light slope above the ball and towards the net, this fact considering the ball low; the projectile, like all the others in tennis, should travel through the face of racquet, along the short cords.
Cheap MLB Jerseys Wholesale http://www.cheapnfljerseyssupply.us.com/


It is the job of the government legal gal and guy attorneys, barristers and others to deal with this and so they have had to learn to deal and work with it.an estimate. In reality theyrose 14%, 3%, 9% and 7%. You see, on the back of each of the sea creature cut outs you will have written a question for a guest to read and answer. Rarely will someone who shares your interests charge more or try to make a profit off of someone in need.
Cheap Jerseys China http://www.cheapnfljerseyschinawholesale.us.com/


Ninety nine percent of them are useless.In their market report for 2008 they made statements such as”Katowice is reaching its maximum level” and “Lodz is abovethe purchasing power of its inhabitants” while at the sametime admitting they could not explain why prices in Wilanow,an upmarket suburb of Warsaw with large numbers of newapartments coming onto the market, had seen price rises of30%. At the conclusion of your articles, make it clear to your readers what they should do. The projectile of fall does not have any relation with a stop-discharge. An amazing 1% of the respondents were able to correctly answer all eight serving size questions.
Cheap Jerseys http://www.cheapwholesalejerseys.us.com/


Below you?ll locate the link to some internet sites that we believe you need to visit.


Usually posts some really fascinating stuff like this. If you are new to this site.


. Never consider a company that has been in business for less than five years. Everyone gets to sing and take part in the dance competition. A flatter swing is less vertical and more rotational, and is the way Stack and Tilt compensates for being more on top of the ball when the downswing is begun. It is still important to warm up for a round of golf as injuries can occur if you do not do so.
Cheap NFL Jerseys http://www.wholesalecheapjerseysnfl.us.com/


comArticle Source: The Best Guide Associated To Article MarketingDecember 12, 2013 | Author: Alfie Mentone | Posted in Business Taking the time to understand the nuances of article marketing and learning how it proves so effective is what will lead to a successful campaign. It is a collecting. Many people do not believe that golf is a physical activity and does not need a warm up. To take this further, with mlm, you can also make money when the people that you sign up recruit members of their own. If you have played or watched sports at any time you will know that positioning is the key to winning or loosing.
Wholesale NFL Jerseys http://www.wholesalechinajerseysnfl.cc/


Below you?ll uncover the link to some websites that we feel you ought to visit.


Leave a Reply

Your email address will not be published. Required fields are marked *


You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>