OT: why are LAMP sites slow?

[Skip Montanaro]

    Paul> I'm talking about the very familiar experience of clicking a link
    Paul> and then waiting, waiting, waiting for the page to load.  You
    Paul> rarely see that happen with Ebay or Google.  It happens all the
    Paul> time with Wikipedia.

It's more than a bit unfair to compare Wikipedia with Ebay or Google.  Even
though Wikipedia may be running on high-performance hardware, it's unlikely
that they have anything like the underlying network structure (replication,
connection speed, etc), total number of cpus or monetary resources to throw
at the problem that both Ebay and Google have.  I suspect money trumps LAMP
every time.

Just as a quick comparison, I executed

    host www.wikipedia.org
    host www.google.com

on two different machines, my laptop here on Comcast's network in Chicago,
and at Mojam's co-lo server in Colorado Springs.  I got the same results for
Wikipedia:

    www.wikipedia.org has address 207.142.131.203
    www.wikipedia.org has address 207.142.131.204
    www.wikipedia.org has address 207.142.131.205
    www.wikipedia.org has address 207.142.131.202

but different results for Google.  Laptop/Chicago:

    www.google.com is a nickname for www.google.akadns.net
    www.google.akadns.net has address 64.233.161.104
    www.google.akadns.net has address 64.233.161.99
    www.google.akadns.net has address 64.233.161.147

Co-Lo server/Colorado Springs:

    www.google.com is an alias for www.google.akadns.net.
    www.google.akadns.net has address 64.233.187.99
    www.google.akadns.net has address 64.233.187.104

We also know Google has thousands of CPUs (I heard 5,000 at one point and
that was a couple years ago).  I doubt Wikipedia has more than a handful of
CPUs and they are probably all located in the same facility.  Google's
front-end web servers are clearly distributed around the Internet.  I
wouldn't be surprised if their back-end servers were widely distributed as
well.

Here's a link to an IEEE Micro article about Google's cluster architecture:

    http://www.search3w.com/Siteresources/data/MediaArchive/files/Google%2015000%20servers%20secrest.pdf

It was published in 2003 and gives a figure of 15,000 commodity PCs.

Here's one quote from the beginning of the article:

    To provide sufficient capacity to handle query traffic, our service
    consists of multiple clusters distributed worldwide. Each cluster has
    around a few thousand machines, and the geographically distributed setup
    protects us against catastrophic data center failures (like those
    arising from earthquakes and large-scale power failures).

Skip