Table of contents

1. Permission basics
2. Permissions on NFS volumes

Permission basics

• In general, files in the cluster are owned by vcalhoun user and trd group.
• Data access is controlled by access control list (ACL). To view the ACL, use the getfacl command.

[msalman@arclogin ~]$ cd /data/mialab2/
[msalman@arclogin mialab2]$ getfacl .
# file: .
# owner: vcalhoun
# group: trd
# flags: -s-
user::rwx
user:jbockholt:rwx
user:msalman:rwx
user:nlewis26:rwx
group::r-x
mask::rwx
other::r-x

The above example shows that /data/mialab2/ is owned by vcalhoun:trd. But jbockholt, msalman and nlewis26 also have read/write/execute (rwx) access to it. Other members of the trd group have read/execute (r-x) permission. If you are the owner of a directory/file, you can change permissions (using chmod) and acl (using setfacl) of it.

The command to set ACL is:

setfacl -P -m u:<username>:rwx <directory>

# recursively:
setfacl -RP -m u:<username>:rwx <directory>

Permissions on NFS volumes

/data/collaboration and /data/users2 are NFS volumes.

The command to set permissions to a specific user is:

nfs4_setfacl -P -a A::<username>@rs.gsu.edu:RWX <directory>

The following will set permissions recursively

nfs4_setfacl -RP -a A::<username>@rs.gsu.edu:RWX <directory>

To check who has permission:

nfs4_getfacl <directory>

It will not show usernames, but an ID number. To know who is the user with the particular ID, use the following:

id <id_number or username>