3.7.0 HP StorageWorks HP Scalable NAS File Serving Software administration guide - HP Scalable NAS 3.7 for Linux (AG513-96002, October 2009)

Quotas are enabled or disabled at the filesystem level. When quotas are enabled,
the filesystem performs quota accounting to track the disk use of each user or group
having an assigned disk quota. When a file owner reaches the hard limit, the
filesystem will not allow the owner to create files or increase the size of an existing
file; any attempts to allocate more space will fail. The file owner will need to remove
files or reduce their size until the disk usage falls below the hard limit.
When you create a filesystem with quotas enabled, you can set default hard limits
for users and groups. These limits apply to all users and groups on the filesystem;
however, you can change the limit for specific users or groups. You can also set a
soft limit for users or groups.
For more information about managing disk quotas for individual users and groups,
see Manage quotas, page 204.
Filesystem restrictions
The following restrictions apply to the PSFS filesystem:
• A PSFS filesystem cannot be used as the root or /boot filesystem.
• A server can mount another non-shared filesystem on a directory of a PSFS
filesystem; however, that filesystem will be local to the host. It will not be mounted
on other hosts in the cluster.
• PSFS filesystems cannot be mounted using the Linux loop device. These filesystems
can be accessed only as SCL-managed “psd” or “psv” devices.
• The loopback driver cannot be used in conjunction with files located on a PSFS
filesystem.
• Swap files are not supported.
• Certain fcntl APIs for user-level applications are not supported. This includes
F_GETLEASE, F_SETLEASE, F_NOTIFY, and mandatory locks.
• All options of the mmap system call are supported on filesystems not mounted with
the dboptimized option. However, when using PROT_WRITE/MAP_SHARED
mmaps, cross-server coherency of the mapped regions is not guaranteed. In addi-
tion, the act of creating a shared mmap for a file will preallocate storage space
for the entire size of the mapping, even if this mapping is larger than the current
file size. All processes using writable shared mmaps to share data must be on the
same server.
• Use of the mmap system call is not supported on filesystems mounted with the
dboptimized option.
• The ETXTBSY mechanism is not supported. Processes will not be prevented from
writing to running executable files.
Configure PSFS filesystems124