Veritas File System 4.1 Administrator's Guide (HP-UX 11i v3, February 2007)

Quota
Quota Limits
Chapter 7112
Quota Limits
You can set limits for individual users to file and data block usage on a file system. You can set two kinds of
limits for each of the two resources:
• The hard limit is an absolute limit that cannot be exceeded under any circumstances.
• The soft limit, which must be lower than the hard limit, can be exceeded, but only for a limited time.
The time limit can be configured on a per-file system basis only. The VxFS default limit is seven days.
A typical use of soft limits is when a user must run an application that could generate large temporary files.
In this case, you can allow the user to exceed the quota limit for a limited time. No allocations are allowed
after the expiration of the time limit. Use the edquota command to set limits (see “Using Quotas” on
page 113 for an example).
Although file and data block limits can be set individually for each user, the time limits apply to the file
system as a whole. The quota limit information is associated with user IDs and is stored in a user quota file
(see “Quota Files on VxFS” on page 112 ).
The quota soft limit can be exceeded when VxFS preallocates space to a file. See “Attribute Specifics” on
page 54 for information on extent allocation policies.
Quota limits cannot exceed two terabytes on a Version 5 disk layout.
Quota Files on VxFS
A quotas file (named quotas) must exist in the root directory of a file system for any of the quota
commands to work. The files in the root directory are referred to as the external quotas file. VxFS also
maintains an internal quotas file for its own use.
The quota administration commands read and write to the external quotas file to obtain or change usage
limits. VxFS uses the internal file to maintain counts of data blocks and inodes used by each user. When
quotas are turned on, the quota limits are copied from the external quotas file into the internal quotas file.
While quotas are on, all the changes in the usage information and changes to quotas are registered in the
internal quotas file. When quotas are turned off, the contents of the internal quotas file are copied into the
external quotas file so that all data between the two files is synchronized.