Scientific analysis servers
Scientific analysis servers
Once you have logged on to one of the login servers you can then ssh
to a scientific analysis (sci) server to do your work.
The sci servers are not directly accessible outside the firewall of RAL (JASMIN’s host instution) so most users will need to access them via a login server.
The following sci servers are available:
Server name | Virtual/Physical (OperatingSystem) | Processor model | CPU Cores | RAM (GB) | /tmp (GB) |
---|---|---|---|---|---|
sci1.jasmin.ac.uk | V (CentOS7) | Xeon(R) Silver 4114 CPU @ 2.20GHz | 8 | 32 | N/A [Note 2.] |
sci2.jasmin.ac.uk | V (CentOS7) | Xeon(R) E5-2630 @ 2.20GHz | 8 | 32 | [Note 2.] |
sci3.jasmin.ac.uk | P (CentOS7) [Note 1.] | AMD EPYC 7402 | 48 | 1000 | 25 |
sci4.jasmin.ac.uk | V (CentOS7) | Xeon E5-2660 @ 2.20GHz | 8 | 32 | N/A [Note 2.] |
sci5.jasmin.ac.uk | V (CentOS7) | Intel(R) Xeon(R) CPU E5-2630 v4 @2.20GHz | 8 | 32 | N/A [Note 2.] |
sci6.jasmin.ac.uk | P (CentOS7), [Note 1.] | AMD EPYC 7402 | 48 | 1000 | 25 |
sci8.jasmin.ac.uk | P (CentOS7), [Note 1.] | Intel(R) Xeon(R) Gold 5118CPU @ 2.30GHz | 24 | 383 | 25 |
Hosts sci[3,6,8].jasmin.ac.uk
are physical servers on a private internal network, so outbound internet access (via NAT) is only
for HTTP(S), so outbound SSH will not work (to hosts outside of
JASMIN) on these machines. If you try to git pull/clone
from external repositories e.g. Github, the operation will timeout with error fatal: Could not read from remote repository
. The solution in this case is to access git pull/clone
over HTTPS instead (check the repo for alternative access details).
The local /tmp
of the virtual sci servers is not available (N/A) for users
as this is used by the VM itself. It also provides no performance advantage as it is not local to the server.
A monitoring utility “Arbiter” is implemented across all sci machines to control CPU and memory usage. This utility records the activity on the node, automatically sets limits on the resources available to each user. Users’ processes are thus capped from using excessive resources, and can be slowed or have memory reduced in response to repeated violations.
Users are not permitted to execute commands which require
administrative privileges. This applies to all hosts in the managed part of
JASMIN where users have SSH login access (for example login
, nx-login
,
sci
, xfer
and hpxfer
machines). In other words, the use of su
or
sudo
is not permitted. Please be careful when typing commands,
particularly if you have multiple terminal windows open on your own computer,
that you do not accidentally attempt sudo
on a JASMIN machine: expect some
follow-up from the JASMIN team if you do!
See also Software installed, below.
Scientific analysis servers are designed for interactive and ad-hoc analysis of data in group workspaces, the CEDA archive, and users’ home directories. For long-running and resource-intensive jobs, users are required to use the LOTUS cluster which offers better I/O performance, parallelism, and fair-share scheduling.
The following guidelines should be considered when using the scientific analysis servers:
top
, or free -h
)top
or ps
Linux commandsEach sci server has the following features:
module
system.Further information on using the software provided on JASMIN can be found here.
See [Note 4] above about privileges: you can only install software for yourself if it can be done with user-level privileges.
Each sci server has:
/work/scratch-pw*
and /work/scratch-nopw2
volumes.