[Beowulf] Naming Convention Survey

[Luc Vereecken]

At 08:28 PM 1/9/2006, Brian D. Ropers-Huilman wrote:
>Simple question, likely a complicated answer. Cluster systems should have up
>to three distinct file systems:
>
>1) a place to compile and keep "stuff"
>2) a bit of disk to use while code is running
>3) potential a bit of disk with special characteristics, likely 
>high-performance
>
>Typically #1 would be called /home. Here at LSU, #2 is typically called
>/var/scratch or /var/local/scratch. Then there is #3. Sometimes we call this
>/scratch and sometimes /work.
>
>My question: what do other folks call these bits of disk?

Our /home is the place for #1. If users/admins have specific programs 
that they want to make publically available, it can be published 
under admin-supervision in /usr/local. Given the number of nodes we 
have relative to network performance, and the potential aggregate 
bandwidth problem to the central server, it is not intended for any 
scratch file storage for running jobs, only for "real" data.

For small, non-bandwidth-sensitive local scratch (#2), we just use 
/tmp, local on each node. Small means there is at least 4GB available 
(up to 30GB on some nodes), but on a regular local disk.

Nodes designed for IO-intensive calculations have a /tmpfast 
filesystem where a raid-0 array is mounted (#3). Sizes are large (as 
large as needed for our current computational problem), throughput is 
high (such that IO/CPU bottlenecks are reasonably balanced for our 
typical problem sizes). If these nodes are used for non-IO-intensive 
jobs, it is nonetheless recommended to move regular scratch files 
(usually /tmp) to /tmpfast. A simple scripted check for the existance 
of this filesystem is sufficient and easy to implement to achieve this.

Our calculational needs do not include the permanent storage of very 
large datafiles, only large scratch files that are discarded after 
job completion.

Luc Vereecken





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