quota(5) File Formats Manual quota(5)
NAME
quota - disk quotas
DESCRIPTION
Disk quotas can be used by the system administrator to limit the number of files and file blocks owned by a user or group on a per-file-
system basis. Separate limits can be established for both the number of files (inodes) and the number of 1 KB blocks for each user or
group. A (preferred) and a limit are established.
For example, user may have soft limits of 1000 blocks and 200 files and hard limits of 1200 blocks and 300 files on the root file system
containing his/her directory and and soft and hard block limits of 100 and 120, respectively, with no explicit file limit(0), on the
mounted file system
A time limit is established for each file system which determines how long a user is allowed to exceed the soft limit. The default time
limit is one week (seven days).
When a user exceeds his/her soft limit, a warning is emitted on the user's terminal. The user can continue to increase utilization over
the soft limit until he/she either exceeds the hard limit or the established time limit. Once either of these events occurs, a message is
sent to the user's terminal and further attempts at file creation and/or increased block utilization will fail. At this point, the user
must reduce his/her use of the exceeded limit below the soft limit to restore normal operation.
At login time, users exceeding quota limits are reminded (via of exceeded quotas and appropriate remedial action. The user can check cur-
rent quota status at any time with the command (see quota(1)).
Quota limits and utilization statistics are maintained by the operating system for each file system for which quotas have been enabled (see
mount(1M) and quotaon(1M)).
Disk quotas are established independently for each user and each file system via the command (see edquota(1M)). This command is also used
to establish the limit for the amount of time users are permitted to exceed their soft limit. The default time limit is one week.
Limits and usage statistics are stored statically in the file on the root of each file system for which they are in effect. This file is
synchronized with information in the kernel by the system call (see quotactl(2)) and whenever an affected file system is unmounted.
Quotas can be enabled automatically at boot or mount time by adding the option to the option list in (see fstab(4) and mount(1M)). By
default, does not enable disk quotas.
Quotas can subsequently be disabled and re-enabled with the and commands (see quotaon(1M)). When quotas are disabled, the kernel does not
maintain usage statistics and the file usage statistics are invalidated by file system activity. Disabling quotas improves performance,
but necessitates running the command (see quotacheck(1M)) to update the kernel and file after subsequently re-enabling quotas.
The command (see repquota(1M)) displays reports of current quota statistics. The somewhat related, but independent, command (see
quot(1M)), collects and reports disk utilization independently of the disk quota subsystem.
The command (see mount(1M)) reports any file systems for which quotas are enabled.
Data Storage Structure
The data structure (defined in is used by the system call (see quotactl(2)) to get or set quota information. This structure contains
fields that are used to store a user's current file and block count and quota limits for a particular file system.
contains the following members:
The data structure (defined in is used by the system call (see quotactl(2)) to get or set quota information for 64-bit filesystems. This
structure contains fields that are used to store a user's current file and block count and quota limits for a particular file system. Note
that VxFS 3.5 will track usage in the dqb64_curblocks field only up to 2 TB.
contains the following members:
NETWORKING FEATURES
Quotas are not fully supported over NFS file systems. However, the command is able to report quota statistics on remote NFS file systems
for which disk quotas are in effect, if the remote system provides the RPC service (see rquotad(1M)).
is provided to allow reciprocal support to other systems.
EXAMPLES
Initial Setup
The kernel must be reconfigured to support disk quotas; see the System Administration manuals. Eligible file systems for disk quota
enforcement are those with mount options and as described in mount(1M) and fstab(4).
For each file system for which quotas are to be enabled, perform the following tasks:
1. Mount the file system.
2. Add to the existing options list in For example, change the string for the root entry to Once this is done, quotas will auto-
matically be enabled for all relevant file systems on system reboot.
3. Create the file in the mount directory of the file system. For example, for the file system, run the command
4. Establish one or more prototype user quotas using the command (see edquota(1M)).
If you want a number of users on your system to have the same limits, use to set those quotas for a prototype user; then use
the command to replicate those limits for that group of users.
5. Turn on the quotas on the file system using For example, run the command
6. Run (see quotacheck(1M)) on the file system to record the current usage statistics.
Adding a New User
To add a new user to the quota system:
1. Use to copy the quotas of an existing user.
2. Run
Adding a New File System to an Established System
Repeat steps 1 through 5 above under "Initial Setup" for the new file system.
WARNINGS
The HP-UX default is to allow This can interfere with the disk quota mechanism. Quotas can be defeated if the command (see chown(1)) or
the system call (see chown(2)) is accessible to a user. The command (see setprivgrp(1M)) can be used to limit access to the system call so
that only a specified group of users are permitted to use the command or the system call.
The command (see sam(1M)) does not yet support disk quotas. When adding new users or file systems, any desired quotas must be established
outside of
HP has added features to the original implementation to ensure correctness of the content of the quotas file when quotas are enabled by and
disabled by (see mount(1M)), thus eliminating the need to run (see quotacheck(1M)). These features are ineffective, however, if and (see
quotaon(1M)) are used to control quotas.
should only be run on a dormant file system to ensure accurate usage information. The options of the command (see fsclean(1M)) report on
the current viability of the quota information.
AUTHOR
Disk Quotas were developed by the University of California, Berkeley, Sun Microsystems, and HP.
FILES
Static information about the file systems
Mounted file system table
User and group quota statistics static storage for a
file system respectively, where directory is the root of the file system, as specified to the command (see
mount(1M)).
SEE ALSO
chown(1), quota(1), edquota(1M), mount(1M), quot(1M), quotacheck(1M), quotaon(1M), rquotad(1M), setprivgrp(1M), chown(2), quotactl(2), vfs-
mount(2), fstab(4).
quota(5)