3.1 Parallel FTP Client Transfers

Parallel transfers involve the creation of child processes to transfer the data between the source and the destination. This process may be either local spawned PFTP client children, remotely initiated PFTP "children," or the combination of both. When the pwidth value is set and a valid multinode configuration file does not exist or multinode has not been activated, the PFTP client will provide parallel data paths to the Movers by spawning multiple processes on the client node using one or more network interfaces (NICs).

The multinode option supports spawning the client processes across multiple machines / nodes and/or multiple interfaces on the remote machines / nodes. This multinode option may be beneficial on processors which support shared file systems, such as GPFS on the IBM SP. Note: if multinode is used in a non-shared file system, the multinode file transfer to the client will be spread across multiple, separate files, which is not the desired behaviour. The client nodes which participate in a multinode transfer are selected from the HPSS.conf configuration file which contains entries with control, and optionally, data interface names or addresses. The number of nodes selected from the configuration file is based on the pwidth value. The starting node is selected using an offset of which is maintained by the PFTP client.

3.1.1 Parallel FTP Client Configuration

The PFTP client requires configuration in the HPSS.conf file to provide optimal performance characteristics.

3.1.1.1 HPSS.conf File

This configuration file is used to specify performance optimization parameters for the PFTP components, the HPSS Movers, and potentially Site specific applications. For details of the implementation of the HPSS.conf file, contact your local HPSS administrator.

3.1.1.2 Local File Functions

The Local File Functions represent performance enhancements using the HPSS parallel protocols where both the HPSS file and the Unix source/destination file are "globally available" to the mover(s) and the PFTP client processes (e.g., GPFS filesystems.) The local file path must be specified in the file: /var/hpss/etc/hpss_mvr_localfilepath.conf. The specified path specified must exist for each PFTP Client/Mover machine.

Configuration Criteria: