Lev Lafayette

It happens rarely enough, but on occasion (such as an upgrade to a database system (e.g., MySQL, MariaDB) or system version of a web-scripting language (e.g., PHP), you can end up with one's Drupal site failing to load, displaying only the error message similar to:


PDOException: SQLSTATE[HY000] [1044] Access denied for user 'username'@'localhost' to database 'database' in lock_may_be_available() (line 167 of /website/includes/lock.inc).


This year the International Supercomputing Conference and TERATEC were held in close proximity, the former in Frankfurt from June 17-21 and the latter in Paris from June 27-28. Whilst the two conferences differ greatly in scope (one international, one national) and language (one Anglophone, the other Francophone), the dominance of Linux as the operating system of
choice at both was overwhelming.

The following is a short tutorial on using BLAST with Slurm using fasta nucleic acid (fna) FASTA formatted sequence files for Rattus Norvegicus. It assumes that BLAST (Basic Local Alignment Search Tool) is already installed.

First, create a database directory, download the datafile, extract, and load the environment variables for BLAST.


mkdir -r ~/applicationtests/BLAST/dbs
cd ~/applicationtests/BLAST/dbs
wget ftp://ftp.ncbi.nih.gov/refseq/R_norvegicus/mRNA_Prot/rat.1.rna.fna.gz
gunzip rat.1.rna.fna.gz
module load BLAST/2.2.26-Linux_x86_64


Having extracted the file, there will be a fna formatted sequence file, rat.1.rna.fna. An example header line for a sequence:

>NM_175581.3 Rattus norvegicus cathepsin R (Ctsr), mRNA

High Performance Computing systems offer excellent metrics for speed and efficiency when using bare metal hardware, a high speed interconnect, and parallel applications. This however does not represent a significant portion of scientific computational tasks. In contrast cloud computing has provided management and implementation flexibility at a cost of performance. We therefore suggest two approaches to make HPC resources available in a dynamically reconfigurable hybrid HPC/Cloud architecture. Both can can be achieved with few modifications to existing HPC/Cloud environments.

The importance of High Throughput Computing (HTC), whether through high performance or cloud-enabled, is a critical issue for research institutions as data metrics are increasing at a rate greater than the capacity of user systems [1]. As a result nascent evidence suggests higher research output from institutions that provide access to HTC facilities. However the necessary skills to operate HTC systems is lacking from the very research communities that would benefit from them.

SSH (Secure Shell) is secure means, mainly used on Linux and other UNIX-like systems, to access remote systems, designed as a replacement for a variety of insecure protocols (e.g., telnet, rlogin etc). This presentation will cover the core useage of the protocol, its development (SSH-1 and SSH-2), the architecture (client-server, public key authentication), installation and implementation, and some handy elaborations and enhancements, and real and imagined vulnerabilities.
Plenty of examples will be provided throughout along with the opportunity to test the protocol.

Whilst it is a loose metric, our little cluster, "Spartan", at the University of Melbourne ran its 1 millionth job today after almost exactly a year since launch.

The researcher in question is doing their PhD in biochemistry. The project is a childhood asthma study:

"The nasopharynx is a source of microbes associated with acute respiratory illness. Respiratory infection and/ or the asymptomatic colonisation with certain microbes during childhood predispose individuals to the development of asthma.

Using data generated from 16S rRNA sequencing and metagenomic sequencing of nasopharyn samples, we aim to identify which specific microbes and interactions are important in the development of asthma."

Moments like this is why I do HPC.

Congratulations to the rest of the team and to the user community.

After using Duolingo for over a year and accumulating almost 100,000 points I thought it would do the right thing and pay for the Plus service. It was exactly the right time as I would be travelling overseas and the ability to do lessons offline and have them sync later seemed ideal.

For the first few days it seemed to be operating fine; I had downloaded the German tree and was working my way through it. Then I downloaded the French tree, and several problems started to emerge.

Gaussian is a well-known computational chemistry package, and sometimes subject to debate over its license (e.g., the terms state researchers who develop competing software packages are not permitted to use the software, compare performance etc). Whilst I have some strong opinions about such a license, this will be elaborated at another time. The purpose here is to illustrate the use of heredocs with Slurm.

High performance computing and cloud computing have traditionally been seen as separate solutions to separate problems, dealing with issues of performance and flexibility respectively. In a diverse research environment however, both sets of compute requirements can occur. In addition to the administrative benefits in combining both requirements into a single unified system, opportunities are provided for incremental expansion.