Answer: Quotas are used to limit a user's or a group of users' ability to consume disk space. This prevents a small group of users from monopolizing disk capacity and potentially interfering with other users or the entire system. Disk quotas are commonly used by ISPs, by Web hosting companies, on FTP sites, and on corporate file servers to ensure continued availability of their systems.
Without quotas, one or more users can upload files on an FTP server to the point of filling a filesystem. Once the affected partition is full, other users are effectively denied upload access to the disk. This is also a reason to mount different filesystem directories on different partitions. For example, if you only had partitions for your root (/) directory and swap space, someone uploading to your computer could fill up all of the space in your root directory (/). Without at least a little free space in the root directory (/), your system could become unstable or even crash.
You have two ways to set quotas for users. You can limit users by inodes or by kilobyte-sized disk blocks. Every Linux file requires an inode. Therefore, you can limit users by the number of files or by absolute space. You can set up different quotas for different filesystems. For example, you can set different quotas for users on the /home and /tmp directories if they are mounted on their own partitions.
Limits on disk blocks restrict the amount of disk space available to a user on your system. Older versions of Red Hat Linux included LinuxConf, which included a graphical tool to configure quotas. As of this writing, Red Hat no longer has a graphical quota configuration tool. Today, you can configure quotas on RHEL only through the command line interface.
1. vi /etc/fstab
/dev/hda11/dataext3defaults,usrquota 1 2
2. Either Reboot the System or remount the partition.
Mount –o remount /dev/hda11 /data
3. touch /data/aquota.user
4. quotacheck –ufm /data
5. quotaon -u /data
6. edquota –u user1 /data
and Specified the Soft limit and hard limit on opened file.
To verify either quota is working or not:
Soft limit specify the limit to generate warnings to users and hard limit can’t cross by the user. Use the quota command or repquota command to monitor the quota information.
