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=== Linux [loginservers
=== Linux [loginserverslogin servers] ===
Revision as of 17:25, 4 January 2016
Servers and Workstations
C&CZ manages ca. 900 Linux workstations and servers, and ca. 900 servers and workstations with MS-Windows, primarily in the domain science.ru.nl. Dual boot Windows/Linux machines are counted twice.
C&CZ manages (for departments) workstations with Ubuntu Linux or MS-Windows. There are also workstations in the PC-rooms and Study area for general use by anybody with a Science login, but also by all RU employees and students and guests with a temporary login. Almost all those machines are dual boot, the user can choose to boot Ubuntu Linux or MS-Windows.
Linux login servers
Two secure shell servers are available for Students and Staff of the Faculty (everyone with a Science account). The primary login server can be reached with the following address:
The name of the backup login server is:
At the moment, lilo points to a machine called lilo4. Stitch points to lilo3.
The ssh finger prints for lilo3 and lilo4 are:
2048 3e:b9:89:4d:53:9b:8f:4a:97:b2:a1:c3:0d:74:34:2c root@lilo3 (RSA) 2048 aa:ad:c0:2e:60:9d:d3:cd:ca:a4:59:7d:d0:d8:4c:68 root@lilo4 (RSA)
In case you are behind a firewall the does not permit outgoing connections to the standard ssh port 22. Our login servers also allow connections to ports 80 and 443.
Recommended ssh client software:
- Linux: Your computer should have ssh installed by default. Otherwise, install the openssh-client package.
- OS X: the ssh client should be available on your Mac.
- Windows: Use MobaXterm, PuTTY or the OpenSSH client provided by Cygwin.
- Android: ConnectBot
Recommended file transfer clients:
Some applications require a PC with MS Windows installed. If you use another operating system, you can make use of a Windows Terminal Server.
C&CZ manages a number of compute clusters, with compute nodes that departments have purchased. In a few cases, departments have created a separate cluster by also purchasing their own head node (master). The largest cn-cluster has a head node purchased by C&CZ. For departments of FNWI the housing and management of clusternodes is free of charge. The cn-cluster is heterogeneous. The newest nodes have SLURM as cluster software, other nodes wil be moved from Torque / MAUI to SLURM. In 2006 the cluster started with Fedora Linux and Sun GridEngine as previous clustersoftware. As of October 2015, the cn-cluster totalled 1220 cores and 8266 GB RAM. Several clusternodes have a GPU with CUDA cores. The CPU-load of the clusternodes is being monitored.
The Astrophysics coma cluster with 920 cores, 7360 GB RAM, 600 TB fileserver storage (as of October 2015), GPU's and Infiniband interconnect is a separate cluster. Separate clusters are also managed for the RU departments Centre for Language Studies en Donders Centre for Cognition.
Sometimes outside of opening hours also the pcs in the computer labs are used as a compute cluster.
On the Do-It-Yourself website each user can see which mail server will store incoming mail for his account. Mail can be accessed with IMAP over SSL. The use of POP3 is supported, but not advised. In every domain managed by C&CZ the alias smtp.science.ru.nl points to the machine that accepts mail with the SMTP-protocol. N.B.: If one uses a (non-RU) Internet provider, our mail server will only accept mail for our (RU) mail-addresses. Most other mail will not be accepted ("Relaying Denied!"). One can prevent this by using the smtp-server of the Internet-provider or by using Authenticated SMTP.
The amount of mail and spam is being logged.
There are several WWW-servers with websites and web applications.
Several servers are used to print jobs. See the printer webpage to see which server is advised in which situation.
These servers share different types of files, e.g. home-directories, application-software and disks for departments and groups. All modern servers only have redundant disks, sometimes by using "mirroring", sometimes by use of a "RAID-array". That means that loss of only 1 disk will not cause any problem for users.
To make it possible for users anywhere on the Internet to use servers and services as if one is connected to the campus network, a VPN service is available.
To make the transfer of large files to others simple, there is an FTP service. It can be accessed through the original FTP protocol as well as through the web HTTP protocol. Anyone with a Science-account who acquired a directory on this server through postmaster, can copy files to that directory in several ways:
- by logging in to a login server like lilo in /vol/ftp/pub/yourdirectory.
- by attaching the network drive: \\ftp.science.ru.nl\ftp
By using an unreadable upper directory containing a secret directory, one can even transfer somewhat sensitive data.
For several software packages there is a license server, that allows use of the software on all pc's, while making sure that the total number of licenses uses is not more than what has been bought. Most of these license servers use FlexNet by Flexera.
Almost all disks that are managed by C&CZ, are being backupped regularly, in order to be able to restore data in case of small or large calamities.