User Tools

Site Tools


faq:start

F.A.Q.

Before You Start

How do I get an account with the CHPC?

Complete the online application on the CHPC user database.

Starting at the CHPC

How do I log into the CHPC supercomputers?

See the User Guide.

Shell & Login Problems

I cannot login because my account has been expired!

You have been locked out because you have exceeded the home directory quota. Submit a helpdesk request to ask for you account to be unlocked so that you can remove excess data. You have until the following Monday morning to so this.

There is a 45 GB quota for data stored in your home directory. Please note that this is separate to your Lustre space. You will normally find a “lustre” directory in your home directory, but this is simply a symbolic link that points to your directory on a completely separate file system. To find the amount of data in your home directory, use the “du” command. You can get help with the “–help” option:

du --help

The -h option will provide the result in “human” readable units. To see how much data you have in your home directory in total:

du -h -d0

To find the amount of data in each directory, drill down one additional level:

du -h -d1

My .bashrc file is ignored when I login!

The non-interactive startup file .bashrc is not executed for interactive shells, only .profile is. To fix this, add the following line to the end of your .profile file:

source .bashrc

I've compiled and installed package XYZ in my home directory but when I type XYZ I get "command not found"

You need to add the path of the bin/ sub-directory for your installation directory to your PATH environment. Add something like the following to your .bashrc file (also see the previous question):

export PATH=/export/home/your_username/XYZ/bin:$PATH

NB: replace your_username with your own user name as allocated for your CHPC account and replace XYZ with the full name of the sub-directory you installed the package XYZ in.

We recommend opt/ so that. for example, if you installed Kactus 3.1.4 in ~/opt/kactus-3.1.4/ (in your home directory, where the ~ refers to the root of your home directory) you would add to .bashrc this line:

export PATH=/export/home/your_username/opt/kactus-3.1.4/bin:$PATH

I've compiled and installed library PQR in my home directory but when I type XYZ I get "libPQR library not found"

You need to add the PQR library location to your LD_LIBRARY_PATH using the following code in your .bashrc

export LD_LIBRARY_PATH=/export/home/your_username/opt/PQR/lib:$LD_LIBRARY_PATH

Where you need to replace your_username with your own user name as allocated for your CHPC account and replace PQR with the full name of the sub-directory you installed the PQR library in.

My job is stuck in the queue and not running. WHY???

Start by getting the numbers and status of your jobs, using the following command:

qstat -awu jblogs

Please use your own user-id, not jblogs!

Now get more information about job number 123456.sched01 with the command:

qstat -f 123456.sched01 

Please use the number of the stuck job, not the made-up number used in this example … Now peruse the output from the the qstat -f command carefully. Near the end will be a line similar to this one:

     comment = Not Running: Insufficient amount of resource: nodetype 

,which is most likely to provide a clue. In most cases, the comment will indeed be “Insufficient amount of resource …”, which may simply indicate that the system is very busy, and there are not enough free compute nodes currently available. However, it may also indicate that you have asked for something that the cluster does not have, such as:

  1. More than 24 CPUs per node for haswell_reg compute nodes, or more than 56 for haswell_fat nodes
  2. More MPI processes than CPUs
  3. Too much memory. Please see this explanation on how to specify the required amount of memory.

Also check that your research programme still has a valid allocation. The scheduler should reject job submissions if you do not have a valid allocation, but if the allocation expired after job submission but before job launch, the job may be stuck in queued mode indefinitely.

/app/dokuwiki/data/pages/faq/start.txt · Last modified: 2025/05/26 11:46 by ccrosby