HP StorageWorks Scalable File Share - Manual (Page 122)

Creating and modifying file systems 5–38
As the user continues to access the OST device, the amount of unused quota reservation continues to drop.
When the amount of unused quota reservation drops below 50MB (that is, 50% of the block reservation),
the quota management system reserves a further 100MB of the user’s quota for use by the OST device.
Note that when a user deletes files from the file system, blocks and inodes are released.
A user may be denied permission to write data before the real block limit is reached. For example, where:
Q
Is the block limit allocated to a user, as set with the
lfs setquota
command
(see Section 5.7.2.6 for more information).
bunit
Is the value specified in the
bunit
option on the file system.
btune
Is the value specified in the
btune
option on the file system.
S
Is the number of OST devices in the file system.
The effective block limit over which a quota overflow may occur is then calculated as follows:
Q - (((1 + (1 - (btune / 100)) * S) + 1) * bunit
This is because there may be up to
(1 - (btune / 100)) * bunit
unused reservations per OST
service, and at least one
bunit
reservation for the MDS.
5.7.2 Configuring quotas on a file system
To configure quotas on a file system, perform the following steps:
1. Verify that the quota option is enabled on the HP SFS system (see Section 5.7.2.1).
2. Enable quota functionality on the file system (see Section 5.7.2.2).
3. Prepare the client nodes to use quotas on the file system (see Section 5.7.2.3).
4. If the file system was originally created when the system was running a version of the HP SFS software
earlier than Version 2.2, configure user and group information on the file system (see
Section 5.7.2.4).
5. Activate quota functionality on the file system (see Section 5.7.2.5).
6. Specify quota limits for users and/or groups (see Section 5.7.2.6).
5.7.2.1 Step 1: Verifying that the quota option is enabled on the HP SFS system
To allow the quota functionality to work, the system-wide
quota
attribute must be enabled. This attribute is
automatically enabled when the HP SFS Version 2.2 system software is installed (or an existing system is
upgraded to HP SFS Version 2.2).
To verify that the attribute is enabled, enter the following command:
sfs> show attribute quota