Implementing Disk Quotas - Red Hat ENTERPRISE LINUX 3 - INTRODUCTION TO SYSTEM ADMINISTRATION Administration Manual

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Reading and comparing: done
Writing pattern 0xffffffff: done
Reading and comparing: done
Writing pattern 0x00000000: done
Reading and comparing: done
Keep in mind that
badblocks
disk drive. For large disk drives, this process can take a long time — quite often several hours.
Important
Many companies (and government agencies) have specific methods of erasing data from disk drives
and other data storage media. You should always be sure you understand and abide by these require-
ments; in many cases there are legal ramifications if you fail to do so. The example above should in
no way be considered the ultimate method of wiping a disk drive.
However, it is much more effective than using the
file using it only marks the file as deleted — it does not erase the contents of the file.
rm

5.9.7. Implementing Disk Quotas

Red Hat Enterprise Linux is capable of keeping track of disk space usage on a per-user and per-
group basis through the use of disk quotas. The following section provides an overview of the features
present in disk quotas under Red Hat Enterprise Linux.
5.9.7.1. Some Background on Disk Quotas
Disk quotas under Red Hat Enterprise Linux have the following features:
Per-file-system implementation
•
Per-user space accounting
•
Per-group space accounting
•
Tracks disk block usage
•
Tracks disk inode usage
•
Hard limits
•
Soft limits
•
Grace periods
•
The following sections describe each feature in more detail.
5.9.7.1.1. Per-File-System Implementation
Disk quotas under Red Hat Enterprise Linux can be used on a per-file-system basis. In other words,
disk quotas can be enabled or disabled for each file system individually.
This provides a great deal of flexibility to the system administrator. For example, if the
tory was on its own file system, disk quotas could be enabled there, enforcing equitable disk usage by
all users. However the root file system could be left without disk quotas, eliminating the complexity
of maintaining disk quotas on a file system where only the operating system itself resides.
is actually writing four different data patterns to every block on the
Chapter 5. Managing Storage
command. That is because when you delete a
rm
direc-
/home/