The pftp_client automatically performs conversion of get and put commands to their parallel equivalents, pget and pput. Some sites have reported degraded performance as a result of this substitution occurring with small file transfers. To accommodate this problem, the Auto Parallel Size = value substanza may be specified in the HPSS.conf file where the “automatic” parallel features will NOT be invoked if the size of the file is less than the value provided. The value may be specified as a decimal number (1048576) or in the format: xMB.
For sites with “Firewalls/ Diodes” installed, it may be necessary to provide specific ports for the data to move between the PFTP Client and the Mover(s). This can be accomplished by specifying the PortRange = value substanza. The syntax of this statement is:
PortRange = ncadg_ip_udp[10100-12100]:ncadg_ip_tcp[10100-12100]
This syntax of the value is identical to DCE’s RPC_RESTRICTED_PORTS environment variable. Only the
Additional options are available for controlling the size of the PFTP transfer buffers, Transfer Buffer Size, and the buffer size for the sockets in the PDATA_ONLY protocol, Socket Buffer Size. The value may be specified as a decimal number (1048576) or in the format: xMB.
The PFTP parallel protocol opens and closes the sockets between the PFTP Client child processes and the Mover(s). The default value for tape was every 512 MB and for disk was the smaller of the size of 64 storage segments or 512 MB. With transfers increasing in performance into the 100MB/sec and greater range, the opening and closing of sockets is another performance problem. The MAX Ptran Size = value substanza has been provided to allow for larger transfers between socket open and closing.
NOTE: in the case of disks, the 64 storage segments is still the overriding specification, so Storage Classes need careful specification to provide very large segments if the value associated with MAX Ptran Size is large. An artificial limit of 250 GB is compiled into the PFTP Client, which should not cause a great concern any time in the near future. Even at 1 GB/sec, this is several minutes! The value may be specified as a decimal number (4294967296) or in the format: xGB.
Under normal operating conditions, the No SAN3P, No Transfer Agent Support, and Special Features Enabled components should remain commented out.
PFTP Client Stanza Example (with suggested contents):
PFTP Client = {
#SYSLOG facility to use for all syslog messages by the Multinode
Daemon.
SYSLOG Facility = LOCAL0
#Set Default Class of Service
;DEFAULT COS = 2
#Debugging Levels ; Debug Value = 1
# Set Default Protocol
;Protocol = PDATA_AND_MOVER
#Set Minimum File Size for auto mapping
#commands to Parallel commands
Auto Parallel Size = 4MB
#Set the Port Range for Port Restrictions on Parallel Transfers
#The syntax has been taken from DCE.
;PortRange =
# PDATA Options
;Parallel Block Size = 512KB
HPSS Installation Guide | July 2008 |
Release 6.2 (Revision 2.0) | 263 |
