<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<div class="moz-cite-prefix">On 05/11/12 20:14, Lee Evans wrote:<br>
</div>
<blockquote cite="mid:001301cdbb92$1eee1070$5cca3150$@leeevans.org"
type="cite">
<meta http-equiv="Content-Type" content="text/html;
charset=ISO-8859-1">
<meta name="Generator" content="Microsoft Word 14 (filtered
medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
@font-face
{font-family:Verdana;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";
mso-fareast-language:EN-US;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p.MsoAcetate, li.MsoAcetate, div.MsoAcetate
{mso-style-priority:99;
mso-style-link:"Balloon Text Char";
margin:0cm;
margin-bottom:.0001pt;
font-size:8.0pt;
font-family:"Tahoma","sans-serif";
mso-fareast-language:EN-US;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:black;}
span.BalloonTextChar
{mso-style-name:"Balloon Text Char";
mso-style-priority:99;
mso-style-link:"Balloon Text";
font-family:"Tahoma","sans-serif";}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri","sans-serif";
mso-fareast-language:EN-US;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
<div class="WordSection1">
<p class="MsoNormal"><span style="font-size:10.0pt;color:black">Hi
all,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:black">We
have a client with a linux web server (apache, mysql, php)
running some wordpress sites.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:black">They
are a relatively high volume site.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:black">We
have been having some trouble with outages, which I suspect
to be due to load (and possibly malicious at that) issues.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:black">The
server locks up or grinds to a halt, there are far more
httpd processes running than normal yet the usage stats
suggest that there aren’t many live users.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:black">My
personal suspicion given the symptoms is a targeted DDoS
attack using some sort of SYN flood to open too many
connections which have a dead end.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:black">Is
there anyone out there that would be interested in helping
us get to the bottom of this?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:black">It’s
beyond our skill set with general server / apache
installation and maintenance.<o:p></o:p></span></p>
<br>
</div>
</blockquote>
<br>
This sounds like very similar symptoms to the ones we suffered
during early deployment of wordpress, which was down to insufficient
memory.<br>
<br>
Check current usage (free or top) and look at the memory used per
httpd process and the max processes in your apache.conf<br>
<br>
Dave<br>
</body>
</html>