<div dir="ltr"><br><div class="gmail_quote">2010/4/15 Boaz Yahav(berber) <span dir="ltr"><<a href="mailto:berber@weber-sites.com">berber@weber-sites.com</a>></span><br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div link="blue" vlink="purple" lang="EN-US">
<div>
<p class="MsoNormal">I guess this is more a theological question.</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Would you build a web site infrastructure that needs to be
highly available using a single machine where the front end servers are virtual
servers?</p>
<p class="MsoNormal">Is this even considered highly available or might it be what's
some may call "partially highly available <span style="font-family: Wingdings;">J</span>"?</p>
<p class="MsoNormal"><br></p></div></div></blockquote><div> </div><div>Using Linux more than a decade, I can say that if you're competent enough as a system administrator (which you should be, if you "go big" and start high-availability-ing your stuff - you need to understand what you're doing) - I've learned that most of the time, a downtime of a Linux system is due to... hardware issues;<br>
<br>So, if you trust your hardware platform (single machine), there is really no point in partitioning your hardware power to multiple "machines" that all do the same thing - you just add more overhead, and more stuff to manage, and when your hardware fails, you're not going to be highly available, but instead, not available at all ;)<br>
<br>So no, I think the key for high availability is: <br><br>* Redundancy - the more the merrier - and nothing should depend on nothing else - meaning - there should be no single point of failure [ = one thing that breaks that makes everything go down. A good example is Shared Storage.... ]<br>
* Quality Hardware (I personally prefer HP - continuing the line of Compaq from the past)<br>* Reliable OS! Can't stress this enough. Of course, reading this on linux-il - you've already made the right choice ;)<br>
<br></div></div>Also remember that your hardware and software are not alone in the game. A website needs to be connected to the Internet. Even if you hardware and software are up 24/7/365 - if your switch/router/network connection dies for some reason, the web site will still be down, as far as the customers care. So you need multiple network connections from multiple ISPs on your own IP netblock that you can advertise to all the links that are currently up :-)<br>
<br>HTH,<br><br>-- Shimi<br></div>