How to Decide if I should upgrade the Ubuntu Server I am using AWS micro instance running Apache HTTP Server and Tomcat servers. I have couple of Web Apps deployed on them where I use port forwarding from 80 to 8080 using Apache. Since I work for a startup (not a sysadmin, and willing to learn), I have to figure out whether we need to upgrade the server from micro to some other instance.  What benchmarks should I check to see if I should update the server? I checked free -m which gives about 300mb of free memory.  But what else should I check to see if the number of connections that Apache is receiving isn't choking it at anytime. Since I use port forwarding how do I check if the Tomcat connections are choking or not.  300mb Free memory is at the instance of time when I checked. But other times when the system may have load, how do I check that?
How do you do load testing and capacity planning for web sites? This is a  about capacity planning for web sites. Related:      What are some recommended tools and methods of capacity planning for web sites and web-applications? Please feel free to describe different tools and techniques for different web-servers, frameworks, etc., as well as best-practices that apply to web servers in general.
I watch a lot of old movies, and I've noticed that American actors of the 1930s and 1940s often spoke in a quasi-generic-posh-British accent.  Katherine Hepburn's accent would be the perfect example. It seems exaggerated, and I imagine it was not common off the stage and screen. What was that? Was it just an accent or was it a dialect? Did real people actually speak that way? I've observed several incidents where users inadvertently posted detailed, sensitive information. For example, a Server Fault user who posted a question with working login credentials to his actual production server, or the Stack Overflow user who posted actual medical records as example data for his question.   What should be the procedure for handling such cases? If $G$ is a group and $G'$ is generated by $\{xyx^{-1}y^{-1}|x,y\in G\}$, then $G'\trianglelefteq G$ and  $G/G'$ is Abelian.  At first, I thought this is easy because I thought $g[x,y]g^{-1}=[gxg^{-1},gyg^{-1}]$. But it was a mistake. I could not prove that it is also subgroup of G and $G/G'$ is abelian. I need help. If I do the following:  import subprocess from cStringIO import StringIO subprocess.Popen(['grep','f'],stdout=subprocess.PIPE,stdin=StringIO('one\ntwo\nthree\nfour\nfive\nsix\n')).communicate()[0]   I get:  Traceback (most recent call last):   File "&lt;stdin&gt;", line 1, in ?   File "/build/toolchain/mac32/python-2.4.3/lib/python2.4/subprocess.py", line 533, in __init__     (p2cread, p2cwrite,   File "/build/toolchain/mac32/python-2.4.3/lib/python2.4/subprocess.py", line 830, in _get_handles     p2cread = stdin.fileno() AttributeError: 'cStringIO.StringI' object has no attribute 'fileno'   Apparently a cStringIO.StringIO object doesn't quack close enough to a file duck to suit subprocess.Popen.  How do I work around this? Incorrect plot using pgfplots (trigonometric functions like cos, sin and tan) I'm trying to plot a function with pgfplots for LaTeX. Unfortunately, pgfplots plots the function incorrectly.  Here is the LaTeX code I use:  \begin{figure}[H] \centering \begin{tikzpicture}     \begin{axis}[xlabel=Gameplays,ylabel=Rating]         \addplot+[gray,domain=1:30]         {0.5 + 0.5 * ((atan(x) * 2 / pi)^11.79)};     \end{axis} \end{tikzpicture} \caption{Omzetten van aantal gameplays tot impliciete rating} \label{fig:omzetten_impliciete_ratings} \end{figure}   Here is how the function should look like:     This is how it is plotted:    Does anyone know what I do wrong?  Thanks in advance! Using apostrophes correctly I've read a great article about the . But there are still some points that are unclear.  Why do we say...   school project but not school's project? car service but not car's service or even cars' service (plural form)? apostrophe usage but not apostrophe's usage or apostrophes' usage? yum install error I can't run a yum command on my server without getting this:   CRITICAL:yum.cli:Config Error: Error accessing file for config file:///etc/yum.conf   This is what my yum.conf looks like:  # This is the fedorafaq.org yum.conf for Fedora Core 5. # # Note that you also need the rest of the configuration # as described at http://www.fedorafaq.org/#yumconf  [main] cachedir=/var/cache/yum keepcache=0 debuglevel=2 logfile=/var/log/yum.log exactarch=1 obsoletes=1 gpgcheck=1 plugins=1 metadata_expire=1800  # PUT YOUR REPOS HERE OR IN separate files named file.repo # in /etc/yum.repos.d   This is what my yum.repos.d looks like:  fedora.repo fedora-updates.repo fedora-updates-testing.repo   The permissions on those files are 0666 and it won't allow me to make them root:root Will my checked luggage freeze in the airplane? I'm taking some freeze-sensitive items in a checked luggage for a short flight. It's cheese, chocolate, toothpaste and wine. I would like to know whether the luggage can get "frozen" in the aircraft. Sometimes it happened to me that my stuff actually was quite cold after the flight, so I'd like to be quite sure. Especially the cheese was really expensive and freezing it would very likely demage it.  Usually I pack everything well in clothes, but this time the things are just too many so it's tough to do more than just protect the wine from breaking.  Some details: It's an A320 flight taking 1.5 hours, with Czech Airlines, from Paris CDG to Prague PRG. How to kill applications I have been playing around with Ubuntu installing new themes and and docks. Sometimes during the installation, whole screen just hangs. What is the best way in Ubuntu to Kill a process/application? Anything similar to Ctrl + Alt + Del of windows? How to check if a macro value is empty or will not create text with plain TeX conditionals? I have a macro which holds some text value, e.g. \macro{some text}. If it is empty, I would like for nothing to appear in the document, but it has some content of any kind which would produce text displayed in the document, I would like a message to appear, "Text: some text".   \macro{} would be considered empty. \def\somedata{}, \macro{\somedata} would be considered empty. \macro{0} would be considered not empty.   I have tried making a TeX conditional which can check if the value is not empty, but nothing I tried works, e.g.:  \ifx #1 {} \else     Text: #1 \fi  \ifx#1{} \else     Text: #1 \fi  \ifx #1 \nil \else     Text: #1 \fi  \ifx#1!="" \else     Text: #1 \fi   What is the correct syntax for creating a conditional in plain TeX with checks if a value is not empty? iOS navigation bar item image size Find subexpression to minimize leafcount after replacment with temporary variable For $G$ group and $H$ subgroup of finite index, prove that $N \subset H$ normal subgroup of $G$ of finite index exists How to change Function (Fn) Key behavior on wireless Logitech keyboard string array with garbage character at end I have a char array buffer that I am using to store characters that the user will input one by one.  My code below works but has a few glitches that I can't figure out:   when I execute a printf to see what's in Buffer, it does fill up but I get garbage characters at the end it won't stop at 8 characters despite being declared as char Buffer[8];   Can somebody please explain to me what is going on and perhaps how I could fix this? Thanks.  char Buffer[8]; //holds the byte stream int i=0;  if (/* user input event has occurred */)  {         Buffer[i] = charInput;         i++;          // Display a response to input         printf("Buffer is %s!\n", Buffer);  }   Output:   tagBuffer is 1┬┬w! tagBuffer is 12┬w! tagBuffer is 123w! tagBuffer is 1234! tagBuffer is 12345! tagBuffer is 123456=! tagBuffer is 1234567! tagBuffer is 12345678!  tagBuffer is 123456789! A Sequence converges to a limit $L \in \mathbb R$ if, and only if, an $N$-th tail of the sequences converges to $L$ for some $N \in \mathbb N$ Why are 50mm Lenses Cheaper? How do I uninstall xcode 5 command line tools? I need to calculate the surface (m2) of external walls of all the buildings in a town. By external walls I mean all the walls of a building or parts of a wall which are not in contact with another building. I have a 2D shapefile of polygons with the cadastral footprint of the buildings, which includes information of the building’s height in the attribute table.  I don’t really know how can I do it… My idea is to convert the 2D file to 3D and use the 3D shapefile to distinguish the external walls from the shared walls (parts of a building that are shared with other buildings) of all buildings, and from there, calculate the total area but I’m not sure whether this can be done with ArcScene.  Anybody knows how could it be done and if there is an automate way to do it? I'd like some suggestions for good reading materials on the Keldysh formalism in the condensed matter physics community. I'm familiar with the imaginary time, coherent state, and path integral formalisms, but lately, I've been seeing Keldysh more and more in papers. My understanding is that it is superior to the imaginary time formalism at least in that one can evaluate non-equilibrium expectations.