quota(5)quota(5)NAMEquota - 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 (pre‐
ferred) 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 con‐
taining 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 estab‐
lished 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
current 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 com‐
mands (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 sta‐
tistics. 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 quo‐
tactl(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 quo‐
tactl(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 enforce‐
ment 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, quo‐
tas will automatically be enabled for all relevant file
systems on system reboot.
3. Create the file in the mount directory of the file sys‐
tem. 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 estab‐
lished outside of
HP has added features to the original implementation to ensure correct‐
ness 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 quo‐
tacheck(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 com‐
mand (see mount(1M)).
SEE ALSOchown(1), quota(1), edquota(1M), mount(1M), quot(1M),
quotacheck(1M), quotaon(1M), rquotad(1M), setprivgrp(1M),
chown(2), quotactl(2), vfsmount(2), fstab(4).
quota(5)
