Yahoo! began life at
Stanford University on a DEC Alpha box running OSF and a
Sparc 20 running SunOS. They served us well for the first
year but we learned that neither system was really
designed for handling a large number of HTTP requests. In
fact we were unable to find any commercial system that
addressed the problems we were facing with scalability.
This was one of the unfortunate realities of being at the
forefront of Web technology. After leaving Stanford we
used a few platforms including SGI IRIX, Linux, and BSDI.
Not being impressed with anything we'd used (in terms of
performance and stability), we were still looking for
alternatives. As Yahoo! grew more popular, both
scalability and stability were becoming critical to our
success. At the time none of us knew anything about
FreeBSD, but after seeing references to it I thought I'd
give it a try.
Having spend many frustrating hours trying to install
other PC OS's, I was a bit skeptical. I had no intention
of spending three days trying to install yet another one.
To my surprise I went to the FreeBSD Web site, downloaded
the floppy boot image, booted a PC with the created
floppy, answered a few install questions, and a few
minutes later FreeBSD was installing over the Net. The
real surprise was when I cam back later to a fully
configured system that actually worked. If anything had
gone wrong with that install it would likely been the end
of that trial. Luckily for us that it was the easiest and
most painless OS installs I had ever experienced.
A couple of days later we added a FreeBSD box to our
cluster of Web servers. Not only did it out-perform the
rest of our machines, but it was more stable. A few weeks
into this experiment and we were sold. Although the
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price was certainly
attractive, it was the stability, performance, and access
to the sourcode that sold us. Ever since then we've used
FreeBSD almost exclusively for production as well as our
development environment. Early on the two big unknowns
were support issues and the future direction of FreeBSD.
The support we've received from the core team as well as
other users has been excelent. This support along with
the source code has allowed us to solve any issues we've
had almost immediately. Likewise we were pleasantly
surprised with the organization and direction of the
FreeBSD project as we learned more about it and the
people involved over the last two years.
We started with a single Pentium 100 box running
FreeBSD 2.0.5. We eventually migrated the rest of our
production servers to FreeBSD and today we have over 50
servers running various versions of 2.1 STABLE. We are in
the process of testing 2.2 STABLE and hope to convert
during the next 6 months. The machines we use range from
a Pentium 100 with 64MB of memory to a PPro200 with 256MB
of memory. When additional I/O performance is needed we
use ccd with stripping over multiple disks. 100Mbps fast
ethernet is used for networking. Overall an extremely
cost effective solution.
FreeBSD has been extremely stable for us. We've seen
over 180 days of uptime on a machine serving over 4
million HTTP requests per day. Performance has been
impressive too. With disk striping using ccd we've been
able to serve over 12 million HTTP requests per day on a
PPro200 with 128MB of memory. One of the only negative
things we've found with FreeBSD has been
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the lack of third party
software. Fortunately this is changing, but there's still
a long way to go. The only way for this to change is for
Yahoo! along with other organizations to convince the
software vendors that there is a big enough market for
their products. One of our big technical challenges is
scaling our services in the face of rapid growth. Looking
forward we are very interested in using SMP to achieve
even better price/performance. FreeBSD on other platforms
(e.g. Alpha) is also interesting from the
price/performance perspective. We are also looking at
FreeBSD to provide other services such as large reliable
RAID file servers. Overall we've found FreeBSD to excel
in performance, stability, technical support, and of
course price. Two years after discovering FreeBSD, we
have yet to find a reason why we should switch to
anything else.
David Filo,
Co-founder of Yahoo!
Taken from FreeBSD News
Issue 1
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