6.1 HP IBRIX X9000 Network Storage System File System User Guide (TA768-96061, June 2012)

3 Setting up quotas
Quotas can be assigned to individual users or groups, or to a directory tree. Individual quotas
limit the amount of storage or the number of files that a user or group can use in a file system.
Directory tree quotas limit the amount of storage and the number of files that can be created on a
file system located at a specific directory tree. Note the following:
• Although it is best to set up quotas when you create a file system, you can configure them at
any time. Configuring quotas later on requires that you unmount the file system, which impacts
system availability.
• You can assign quotas to a user, group, or directory on the GUI or from the CLI. You can also
import quota information from a file.
• If a user has a user quota and a group quota for the same file system, the first quota reached
takes precedence.
• Nested directory quotas are not supported. You cannot configure quotas on a subdirectory
differently than the parent directory.
• The existing quota configuration can be exported to a file at any time.
NOTE: HP recommends that you export the quota configuration and save the resulting file
whenever you update quotas on your cluster.
How quotas work
A quota is delimited by hard and soft storage limits defined either in megabytes of storage or as
a number of files. The hard limit is the maximum storage (in terms of file size and number of files)
allotted to a user or group. The soft limit specifies the number of megabytes or files that, when
reached, starts a countdown timer that runs until the hard storage limit is reached or the grace
period elapses, whichever happens first. (The default grace period is seven days.) When the timer
stops for either reason, the user or group cannot store any more data and the system issues quota
exceeded messages at each write attempt.
NOTE: Quota statistics are updated on a regular basis (at one-minute intervals). At each update,
the file and storage usage for each quota-enabled user, group, or directory tree is queried, and
the result is distributed to all file serving nodes. Users or groups can temporarily exceed their quota
if the allocation policy in effect for a file system causes their data to be written to different file
serving nodes during the statistics update interval. In this situation, it is possible for the storage
usage visible to each file serving node to be below or at the quota limit while the aggregate storage
use exceeds the limit.
There is a delay of several minutes between the time a command to update quotas is executed
and when the results are displayed by the ibrix_edquota -l command. This is normal behavior.
Enabling quotas on a file system and setting grace periods
Before you can set quota limits, quotas must be enabled on the file system. You can enable quotas
when you create the file system or at a later time.
24 Setting up quotas