Everyone knows that PHP opcode caching, or any kind of PHP caching for that matter, is not possible with suPHP. This is a trade off of choosing security over performance. The performance hit of running scripts under suPHP is, however, significant. It’s so significant that pages take noticeably longer to display at the browser. Also, the server load goes through the roof during traffic spikes.
The workaround we’re presenting in this post doesn’t require any compromise in terms of security. You get to keep suPHP with its security blanket but also get a tremendous performance boost from caching. The caching in question comes from Varnish Cache, the open source HTTP accelerator that runs in front Apache (or any other Web server for that matter). We’ve developed a Varnish cPanel script or plugin that allows anyone to run Varnish. The script installs, configures, manages, and integrates Varnish with cPanel without you needing to do any maintenance from the terminal.
Varnish Cache is so powerful that the performance gains surpass that of PHP opcode caching! Both internal and independent benchmarks have shown that our cPanel Varnish Plugin (and VCL) performs better than the fastest Web server in the market including Nginx, Litespeed, and Lighttpd. Read more on the results.
The following video shows how one can easily install the Varnish cPanel script:
Here’s some feedback from people that are using the script: http://www.unixy.net/secure/knowledgebase.php?action=displayarticle&id=25
That’s all folks!
It tends to be difficult to prove uselessness in the unixy world because people can get quite creative with commands in shell scripts. Tools that may appear to be useless to some could be indispensable to others. And as the saying goes: one man’s trash is another man’s treasure. Following our six cool unixy command entry, here’s the uncool list of unixy commands. So here’s to hoping this short list is no one’s favorite!
According to Wikipedia:
Discordianism is the modern religion worshipping Eris (also known as Discordia), the Greco-Roman Goddess of Chaos.
Ok… Next.
“:” is a built-in Bash command and not a binary per se. It does nothing… But its main use remains in the dark side of computing – shell fork bombing (Caution: :(){ :|:& };:).
yes is the annoying one. It takes quite a bunch of Ctrl-C’s to kill it. But it’s there for the curious cat. And do you know what happened to that cat? yes…
Long live MS-DOS!
UNIXY is pleased to announce the beta release of the Varnish cPanel script. Read about it all here: http://www.unixy.net/varnish
Cheers!
We’ve compiled a list of six Unix/Linux tools that are cool and useful. From checking the weather via your terminal to having a sysadmin walk you through a difficult task. Interestingly, most of these tools were released decades ago! Read on…
kibitz is a terminal tool that can be used by a mentor to assist his or her apprentice. It essentially makes what is normally one private terminal session visible to both parties providing bi-directional interactivity. The mentor can then walk the apprentice through various tasks and howtos. A typical session looks like the following to the mentor:
Whatever commands or text that the mentor or the apprentice types is seen on the other end. It looks like this to the apprentice:
tload is a neat tool that displays the load average on the terminal in a form of character drawings. It gives an interesting visual of the system load (/proc/loadavg) over time – time being an adjustable parameter. Without further ado, here’s a screen shot of tload in action:
catchsegv helps one diagnose programs that segfault. If you’re dealing with an app that segfaults frequently, start it up with catchsegv and watch it produce a snapshot of CPU registers, memory maps, and backtrace at the time of the segfault! Here’s a snapshot of it in action:
For those of you who are familiar with the program screen, dislocate is its grandfather.It’s neat tool that allows one to detach programs from the pseudo terminal and reattach to them whenever needed. This is tool for those with slow or unstable terminal sessions that are prone to disconnect.
tac is a command line tool that reads a file in reverse order. It’s ideal for log sifting tasks where one’s interest is in grep’ing the most recent entries.
# cat /var/log/sip
Target 1… DONE
Target 2… DONE
Target 3… DONE
# tac /var/log/sip
Target 3… DONE
Target 2… DONE
Target 1… DONE
weather is an expect-based program that runs from the terminal and grabs weather information from rainmaker.wunderground.com. Wunderground runs a public weather service on port 3000. weather leverages this service to pull weather data by city and displays it on the terminal. Here’s a sample run:
$ weather HOU
<snip>
Enter 3-letter city code: HOUWeather Conditions at 12:53 PM CST on 24 Dec 2010 for Houston Intercontinental, TX.Temp(F) Humidity(%) Wind(mph) Pressure(in) Weather========================================================================63 70% ESE at 10 30.07 OvercastForecast for Houston, TX406 am CST Fri Dec 24 2010.Today…Mostly cloudy with a 30 percent chance of showers. Highsin the upper 60s. Southeast winds 10 to 15 mph..Tonight…Showers likely and isolated thunderstorms. Lows in themid 40s. Northeast winds 5 to 10 mph in the evening becomingnorth and increasing to 15 to 20 mph after midnight. Chance ofrain 70 percent in the evening decreasing to 60 percent after<snip>
That’s all folks! I hope you enjoyed this entry.
Hitting the news today is a concerted DDoS attack effort directed at Amazon as vendetta for its role in ousting Wikileaks.org off its hosting cloud. The attackers are so determined they are asking everybody on the planet to download this program called Low Orbit Ion Canon (LOIC) and launch it against Amazon. In this post, we’rel sharing a flaw in the program that we think can be used to mitigate the attack, to an extent.
The program is written in C# with its source code available for anyone to inspect it and modify it. In fact one has to compile the code in order to use the tool. The flaw in this program is apparent in the source code of the program. In file HTTPFlooder.cs at line 63, the payload of the request is constructed like this:
byte[] buf = System.Text.Encoding.ASCII.GetBytes(String.Format(“GET {0} HTTP/1.0{1}{1}{1}”, Subsite, Environment.NewLine));
This is at the heart of the attack. It consists of a flood of HTTP GET request using protocol 1.0. These kind of attacks are difficult to defend against because the request looks very similar to a legitimate request coming from a typical Web user. The request flows through several layers in the OSI stack and exhausts a lot of computing resources – all the way to the 7th logical layer of the OSI model.
But notice that this request is missing the host header (Example: Host: www.amazon.com). This fact alone can help with filtering the attack. One could ensure that all requests contain this important header either in the Web server configuration (imperfect solution). The optimal solution, however, is to introduce specialized ASIC deep packet inspection devices with proper signatures to filter out the attack.
That’s all folks!
JFK once coined the phrase to promote his efforts around building a dam back in 1963 in a desperate push to revive the economy.I’m afraid I’m going to put the above aphorism in a not-so-bright light. There are many floating startups on the Web who have been valued at exorbitant sums. The valuations are so excessive that many folks are hinting at another dot com bust.
Let’s step back a few years to go over some of the precursors of today’s state of affairs. Here’s a very concentrated but less deserving recount to what I think has led to this nonsense. In 2007, the US triggered a world-wide financial crisis due to many years of accumulated recklessness by financial institutions. The illiquidity was so staggering that banks stopped lending money to other peer banks and consumers. This deadlock was so extreme that the crisis almost rivaled the Great Depression.
The Fed intervened by making an all-you-can-eat virtual cash box available to these banking institutions. The several rounds of cash infusions were meant to encourage the banks to lend in the hopes of kick starting the ailing economy. Alas, banks kept the cash to artificially increase their liquidity levels and avoid the looming stress tests. The availability of these assets and the terms under which they were lent made it almost unnecessary for the banks to try to seek a return on the freely available cash. Again, why risk lending when you can artificially make the balance sheet look good and honker down in safety waiting for the storm to pass?
With this excess in cash and the effects of the crisis, banks had no reason to lure cash-wealthy individuals with high interest rates. In fact, the interest rates dropped dramatically. This fact alone is crucial in understanding the current state of affairs in this Web economy. Here you have a lot of cash-wealthy individuals with poor interest rates and almost no other way to get a higher return.
The need for higher returns means that these investors, and there are many of them right now, have to take more, thought-to-be-calculated, risk; add to it Google’s acquisition success stories every now and then, and you have the perfect oil to fire ratio to get us where we are today. We’re not finished yet. Expect one or two more years before it bursts. The good news for some folks is that the world economy would have recovered well by then to sustain the Internet down cycle but it remains bad news for those making a living on the net like us.
Here we are rising in concert unaware of the looming low tide ahead. Enjoy the view while it lasts.
That’s all folks! I hope you appreciate this article.
