Websites can be very useful for HPC to allow easier access. Recently we had an issue with a website we use and learned a few things on the way. Know your users A website has been running fine for a number of months – and building up a user base. However we recently hit an Read more
Limits on runtimes Running jobs on a supercomputer can sometimes involve letting the job run for a long time. A long time in this instance is longer than the default expected maximum runtime for a particular type of job. At Cardiff we have 2 types of jobs which we have setup our supercomputer for. Serial Read more
This Thursday (the 25th February), ARCCA will be holding a drop-in session in the Trevithick library room 1.15, from 2pm to 3.30pm. These drop-in sessions are an opportunity for the community to meet up with ARCCA in order to ask us questions, suggest ideas, or plead for help! As part of this initial session at Read more
How would you like a tool that would allow you to: Write and maintain workflows more efficient and sophisticated than an existing job submission script. Create dependency trees of tasks that will run at the click of a button, with automatic optimisation so that multiple tasks may be run in parallel. Revision control your tasks Read more
It has been a long summer and it is time again to create a little post for a recent encounter on our supercomputer. Errors in Perl Perl is a common language which is very common within the Genomic communnity. Recently we had an interesting Perl issue where a job would just run for its maximum Read more
Using accelerators such as GPUs and Intel Phi technologies are becoming a popular method to extend the performance of certains codes. ARCCA is holding a research seminar which covers this topic. All are welcome to attend, even if you are not planning to use the technologies its is great to see the cutting-edge research Cardiff Read more
Just like an iceberg, floating point numbers can have hidden danger lurking just under the surface. A recent email through a mailing list reminded me about the subtlties of handling floating point numbers. Floating point numbers are represented by mantissa*(base**exponent), see floating point numbers. There are many occassions where programmers may forget that floating point Read more
Anyone who might have read earlier posts might have come across previous post on Galaxy. This used DRMAA to submit jobs when using a PBS Pro as a job scheduler. However recent issues whilst we upgraded our systems uncovered some unexpected issues with DRMAA. Going native with DRMAA First issue is with a feature of Read more
Another month has passed and we have been very busy in ARCCA at Cardiff University with installation of the new hardware and installing new services. These are a few of the reasons why updates in the past few weeks have been infrequent but as I keep saying to myself: Must do better… However recently we Read more
Recently we had a user report a problem where they had managed to start copying the complete filesystem of a compute node into their home directory. Fortunately for us we had setup quotas on our users home space so it stopped when it filled up their quota but it seemed it was all due to Read more
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