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Durham University

Computing and Information Services

Linux Timeshare

The Linux timeshare service (Mira) is accessible at mira.dur.ac.uk, via SSH access internally and externally and X-2go, which offers fast, secure, graphical log-ins both internally and externally.

Mira is designed to be used by staff and students for Learning and Teaching, its available 24x7 to allow Students to work outside class time.

Mira comprises of two physical servers running the same version of Debian desktop (v9 - Stretch) as PCs with Linux Desktop Service installed to form a High Availability Cluster using pacemaker and corosync.

Hardware Specification

2 x Dell PowerEdge R930 Servers each with:-

4 x CPU Sockets - Intel(R) Xeon(R) CPU E7-8860 v3 @ 2.20GHz
2 Threads per core and 16 Core(s) per CPU Socket

256GB RAM

Accessing Mira

From a PC with Windows Managed Desktop Service Installed

  • To display the Mate desktop:
  • Login into AppHub and launch X2go-Mira r2
  • Click Start on the Windows toolbar and from the pop up menu select All Programs > X2Go Client for Windows A window will be opened at which you can enter your CIS username and password and after successful authentication, the Mate desktop will be displayed.
    • Using Putty:
    • Login into AppHub and launch Putty. Putty is a secure and easy to use client but if you have trouble connecting using the Putty software, please see the FAQ.

From a PC with Linux Managed Desktop Service Installed

Mira and PCs running Linux Managed Desktop Service are same Debian 8 build

  • To display the Mate desktop:
  • Click Applications > Internet > X2Go Client
  • You will need to set the session type to "MATE". The hostname is mira.dur.ac.uk
    • Using X2Go: You can download the latest X2Go client from x2go.org. You will need to set the session type to "MATE". The hostname is mira.dur.ac.uk
    • Using Putty: if Putty is not installed you can download it. Enter the Host Name as mira.dur.ac.uk, select the Protocol to be SSH and select Connection > SSH > Preferred SSH protocol version to be 2. You can save this set-up as Mira. Click Open and enter your CIS username and password.
    • For Linux machines, x2go is probably included with the distribution and installed through the package manager.
    • Using SSH from Linux: type ssh -X mira.dur.ac.uk The -X option enables X11 forwarding which is necessary for graphical applications.

From unmanaged Windows, MAC or Linux PCs

  • Using X2Go: You can download the latest X2Go client from x2go.org. You will need to set the session type to "MATE". The hostname is mira.dur.ac.uk
  • Using Putty: if Putty is not installed you can download it. Enter the Host Name as mira.dur.ac.uk, select the Protocol to be SSH and select Connection > SSH > Preferred SSH protocol version to be 2. You can save this set-up as Mira. Click Open and enter your CIS username and password.
  • For Linux machines, x2go is probably included with the distribution and installed through the package manager.
  • Using SSH from Linux: type ssh -X mira.dur.ac.uk The -X option enables X11 forwarding which is necessary for graphical applications.

Cron Jobs

You may use the standard Linux cron facility on the Mira to execute scheduled commands. This is not intended to be used to start long-running or very resource-intensive jobs - the High Performance Computing service is provided for that purpose. You are also requested not to schedule jobs to be run at very high frequency (e.g. more than once an hour). CIS reserves the right to kill any jobs that compromise the usability of the service for other users.

Cron jobs are defined using the standard Linux crontab command: refer to its manual page for details.

The cron service on Mira is clustered across both of the Mira servers and backed up on the NetApp filers. This means that:

  • Using the crontab command as a particular user from any one of the Mira servers manipulates a single crontab file for that user, shared by all the servers, so it doesn't matter which Mira server you are logged into when you do this.
  • At any one time, only one of the Mira servers will be running cron jobs, on behalf of the whole timeshare service.
  • If a particular Mira server is down for maintenance, or because of a fault, users' cron jobs will still get run.
  • All users' crontab files are regularly snapshotted and backed up, and so can be recovered, by request to the Service Desk (for instance, if accidentally deleted).

If you need to know which Mira server is currently running cron jobs (for instance, if you want to kill one of your running jobs), use the command crontab -c from any Mira server: this will display the name of the current cron server, and then you can log into that server explicitly.