Study Notes

First Part: Quota

Linux’s quota is used to configure the user’s harddisk spaces in order to prevent few users occupy nearly the most of resources.we could configure the quota by following steps:

1.Add “usrquota” to the fourth table position of “/etc/fstab”,for example:

 /etc/hda7    /home    ext2    default, usrquota,1,2 

2.Create two files in the identified partition:

 # touch /home/quota.user
 # touch /home/quota.group 

and then grant the privileges:

 # chmod 600 /home/quota.user
 # chmod 600 /home/quota.group 

3.reboot the system
4.Issue the following command to configure quota for identified user:

# edquota -u username 

Second Part: Limitation
Hard limitation: user can not overflow the specified limitation
Soft limitation: when spaces used reach the specified limitation,system will display a worning message.

# ulimit
# ulimit -a 
(list all limitation parameters which including
 cpu time and counts of files opened.)
 

There are two ways to configure the limitation:

1.Add “ulimit” lines to /etc/profile
2.Modify the /etc/security/limits.conf.It is very important.When I installed Oracle 10g in Red Hat,this file always was modified by adding hard and soft limitation for nproc.The formation of /etc/security/limits.conf is listed here:

    domain    type    item    value 

domain: this parameter startes with “@” first and contains username and group name.if “*” is used,it means all the users and groups.
type: this parameter indicates whether the limitation is hard or soft.
item: this parameter indicates which resouce will be limited.
value:this parameter indicates the setting value.