Skip to content | Change text size

eSolutions home

Quick links


 

Changes to SNG Environment

Table of Contents

General Information

Technical Information

Introduction

The UNIX services delivered via 'sng' will be changing as the hardware platform underpinning the service is being upgraded.

  • This is part of the ITS Service improvement and Hardware refresh program.
  • The new 'sng' service will comprise a redundant pair of faster servers, one server will be placed at each data centre to provide a Disaster Recovery (DR) capability.
  • The old 'sng' hardware will be re-deployed to extend the useful life of hardware supporting other ITS services.
  • The same user account and password for both Unix and Linux teaching environments.
  • The new AFS service is easier to administer - more modular, resilient, scalable and secure. The AFS servers will also be distributed between the two data centres.
  • Unlike the NFS service, the new AFS service has working quotas.
  • The removal of NFS in all its forms has long been a goal of ITS.

File system changes

Home directories have been moved to a new filespace called AFS. (Linux users will be familiar with this).

Previous home directories were located at a path: /its/userN/L/username where N was a number between 1 and 8, and L was the first letter of the username.

New home directory location after 10 February: /afs/monash/users/L1/L2/username where L1 and L2 are the first and second letters of their username.

When you log in after 10 February, you might not see any files in your home directory. Your files remain in the old home directory (/its/userN) and are available in read-only mode. Users will need to copy their files into the new home directory in order to edit them.

The old home directory will be removed at a later date and users will be advised when this is to happen.

Note: Both Linux and SNG environments share the same home directory, so users compiling their own code may wish to create separate directories for i386 and SUN binaries.

How to copy files

To copy files from the old NFS directory to the new AFS directory a user might type something like:

For csh based shells: cp -r /its/user?/?/$user ~ For bash based shells: cp -r /its/user?/?/$USER ~ note the upper case.

Bash users might prefer to use

cp -r $NFS_HOME/* ~

If the command fails due to exceeding disk quota, delete some of the copied files before trying again.

The above command copies the user's entire directory. Users may wish to adapt the above command to only copy the files they really need.

For example, if a user wishes to copy a file called myfile from a sub-directory of their NFS directory called mysub to their home directory they might type:

cp /its/user?/?/$user/mysub/myfile ~

Passwords

If you cannot access SNG after February 10, you will need to reset your password, for the specific machines, SNG, Linux and webedit.

To do this, go to http://www.monash.edu.au/students/computer/ and select the link Passwords for Subject/Unit specific computers

Click on the link Set Passwords for Specific Systems, e.g. Linux, SNG, Webedit and follow the instructions to change your password.

Note: The default action of this page changes your AuthCate password and your other system passwords to the same new password. If you do not wish to change your AuthCate and Novell password, uncheck the boxes for Authcate and Novell. Check the boxes of the passwords you wish to change, i.e. Linux/SNG, webedit. This will reset your Linux, SNG and webedit passwords to all the same word.

Linux users need to be aware that after February 10, if they use the passwd command whilst logged into the service to change their password under Linux it will change both their Linux and SNG passwords, as ITS has moved to a single Kerberised password file for both the Linux and SNG environments.

Best Practice Unix Computing

Set up separate directories for Linux and Solaris binaries.
Avoid password-less login and long running jobs.

Users might wish to use SSH with its password-less features. Unless a password is typed a user will not gain the Kerberos tickets or AFS tokens needed to get access to their home directory. There are possible ways to partially overcome this problem, but the subject is still under investigation.

Similarly when a user logs out, long running jobs, such as web servers, would also normally lose access to the user's home directory, unless special steps are taken. This too is still under investigation. One solution is for users to always login with a password and not to leave jobs running when they logout.

Where long running jobs are unavoidable e.g. student web servers, create a directory in /scratch and run the job from there.

Hardware and operating system changes

SNG is being replaced by two new machines which will be named SNG-1 and SNG-2. The name SNG will become an alias (similar to the way the name Silas became an alias for SNG) that connects to one or the other machine at random. The new SNG environment has DR capability e.g. if there is hardware failure on one machine, the service on SNG is not affected.

The new SNG machines will initially run Solaris 9, a minor upgrade from the Solaris 8 run on the current SNG. Binaries compiled for SNG will almost all run without modification on the new machines. It is expected that only a very few programs will have any difficulty in this regard - only those that try and interpret the operating system's internal structure - e.g. top, vmstat and so on, and such programs should need nothing more that a recompile.

Disk Quota

See http://www.its.monash.edu.au/staff/systems/linux/technical/afs/index.html