Directory Permissions and File Sharing
If you are unfamiliar with Linux file permissions you should consider reading sections 5.1 and 5.2 of this Intro to Linux course (from the University of Surrey) first.
Home Directory Permissions
The default permissions on your home directory on the CSF allow access to you (the user) only. The directory is private to you.
Every user on the CSF also belongs to a unix group on the system. This usually represents your research group, but could represent your school or faculty if your access to the CSF is the result of a school or faculty contribution. For example, users in the Department of MACE are members of the mace01 unix group on the CSF.
It is possible to allow other users in your unix group to access your home directory (e.g., to share files), but this is not the default.
You can run the commands in bold at the login node prompt below. For example:
[username@login1 [csf3] ~]$ ls -ld $HOME drwx------ 37 username zz01 4096 Aug 15 09:59 /mnt/iusers01/zz01/username ||_||_||_| | | | | | +--- Your unix group (based on the CSF contribution you are assigned to) | | | | | | | +-- (---) indicates others (all users) CANNOT access your HOME dir | | +----- (---) indicates people in your group (zz01) CANNOT access your HOME dir | +-------- (rwx) indicates user (you) CAN read, write and execute (enter) your home directory. | +----- directory (will be a dash - if looking at a file's properties)
If you want colleagues in your group to be able to read and copy some of your files, you can set group permissions with the chmod command as follows:
[username@login2 [csf3] ~]$ chmod g+rx $HOME
#
# This adds group read and execute
# permissions to your home directory.
Let’s check how it looks now:
[username@login2 [csf3] ~]$ ls -ld $HOME
drwxr-x--- 37 username zz01 4096 Aug 15 09:59 /mnt/iusers01/zz01/username
|_|
|
+---- Now members of your group (zz01) CAN read and execute (enter) your
HOME dir but notice they CANNOT write to it.
The default file permissions within home directories should be sufficient to now allow people from your group to read the contents of the files and to copy them to their own home directory. If opening the permissions to all members your group is too wide-open, then please let us know who you would like to have access, and we will advise further.
It is highly recommended that you never give anyone else write (w) permission to your directory or files as this allows them to modify or delete them.
Please note that directory permissions override file permissions. Also be aware that groups can be very large and contain a lot of people with whom you do not directly work. If you want your colleagues to be able to edit / write new / delete files in your area please email its-ri-team@manchester.ac.uk us for advice.
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Scratch Directory Permissions
Default permissions on your scratch directory are the same as on your home directory – your scratch directory is private to you. As with the home directory, it is possible to change the permissions on your scratch directory to allow your colleagues to access your files.
NOTE: When working with scratch permissions you must use the direct path to your scratch directory:
/scratch/username
#
# Use your own username here
NOT the symnlink/shortcut you have in your home directory. Thus the command to check your scratch permissions would be:
ls -ld /scratch/username
If you need to change your scratch permissions then the procedure is the same as for home – see above.
Remember: the scratch filesystem IS NOT backed up. It is highly recommended that you never give anyone else write (w) permission to your directory or files as this allows them to modify or delete them.
Please note that directory permissions override file permissions. Also be aware that groups can be very large and contain a lot of people with whom you do not directly work. If you want your colleagues to be able to edit / write new / delete files in your area please email its-ri-team@manchester.ac.uk for advice. |
Group Research Data Storage
Some groups have an allocation of Research Data Storage (RDS) on the CSF. This is additional storage that can provide a lot more capacity than your group’s home area – usually several TB’s worth of storage. RDS storage is backed-up, just like your home directory, and is suitable for long-term storage of important files (e.g., data-sets, results).
For example:
/mnt/fac01-rds/smith-project/
# #
# # The directory name usually indicates the PI and project name
#
# fac is usually a short form of your faculty
which usually contains a directory for each person authorised to use the space and sometimes shared directories.
The permission in these areas vary depending on the group in question. The information above will still be applicable in some cases. If you need help organising your group area or the permissions for it please email its-ri-team@manchester.ac.uk .