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Our problems tend to be not only computationally intensive
but also large. As a result, disk space had to be worked
into our design.
The two most common approaches are either to put significant
disk on each node and then create a virtual filesystem, using
somthing like the Parallel Virtual File System (PVFS)
or creating a large disk server with a high speed connection
to the cluster.
Both approaches have drawbacks. The PVFS approach is dangerous
because it means relying on fairly immature software. In addition,
unless we wanted to use a Redundant Array of Inexpensive Disk (RAID)
greater than zero (meaning we would have to mirror our data), we could run into problems whenever
a node became unavailable.
The disk server approach also has drawbacks. Many of our applications
have significant IO requirements and a gigabit connection still
has latency issues.
We decided to follow a model that allows the greatest
flexibility in programming styles.
Our solution was a combinitation of two
approaches. We put in a large case:
- two dual process 1.2 GHz Athlon boards
- a gigabit network card
- a 100 megabit network card
- IDE raid control cards with 2.4 terabytes of disk.
The total cost of this unit was less than $9000.
In addition, on each node we put a 60 gigabyte disk.
For jobs that have significant IO requirements the
local disk can be used. For large initial and final data, the
disk server is available with a high speed connection.
Next: BUILDING AND SETUP
Up: DESIGNING
Previous: PGI vs. Intel
Stanford Exploration Project
6/8/2002