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

Shared SAN devices
Before a SAN disk can be used, you will need to import it into the cluster. This step
gives HP Scalable NAS complete and exclusive control over access to the disk. During
the import, the disk is given a unique global device name. The servers in the cluster
use this name when they need to access the disk.
Cluster Volume Manager
The Cluster Volume Manager can be used to create dynamic volumes consisting of
disk partitions that have been imported into the cluster. Dynamic volumes can be
configured to use either concatenation or striping. A single PSFS filesystem can be
placed on a dynamic volume.
The Cluster Volume Manager can also be used to extend a dynamic volume and the
filesystem located on that volume. Other Cluster Volume Manager operations include
recreating or destroying a volume.
PSFS filesystems
PSFS filesystems can be created on either basic volumes or dynamic volumes. A basic
volume is a single disk, disk partition, or LUN imported into the cluster. Dynamic
volumes consist of one or more imported disks, disk partitions, or LUNs and are
created by the Cluster Volume Manager.
The PSFS filesystem provides the following features:
• Concurrent access by multiple servers. After a filesystem has been created on a
shared disk, all servers having physical access to the device via the SAN can
mount the filesystem. A PSFS filesystem must be consistently mounted either read-
only or read-write across the cluster.
• Support for standard filesystem operations such as mkfs, mount, and umount.
These operations can be performed either with the Management Console or from
the command line.
• Support for existing applications. The PSFS filesystem uses standard read/write
semantics and does not require changes to applications.
• Quotas for users and groups, including both hard and soft limits.
• Journaling and live crash recovery. Filesystem metadata operations are written
to a journal before they are performed. If a server using the filesystem should
crash during an operation, the journal is replayed and any journaled operations
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