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Chapter 2 HPSS Planning
HPSS Installation Guide September 2002 77
Release 4.5, Revision 2
• Mover to Mover data transfers (accomplished for migration, staging, and repack
operations) also will impact the planned Mover configuration. For devices that support
storage classes for which there will be internal HPSS data transfers, the Movers controlling
those devices should be configured such that there is an efficient data path among them. If
Movers involved in a data transfer are configured on the same node, the transfer will occur
via a shared memory segment (involving no explicit data movement from one Mover to the
other).
2.6.11 Logging Service
Logging Services is comprised of the Log Daemon, Log Client, and Delog processes.
If central logging is enabled (default), log messages from all HPSS servers will be written by the
Log Daemon to a common log file. There is a single Log Daemon process. It is recommended that
the Log Daemon execute on the same node as the Storage System Manager, so that any Delogs
executed by the Storage System Manager can access the central log file. If the central log file is
accessible from other nodes (e.g., by NFS), it is not required that the Log Daemon execute on the
same node as the Storage System Manager.
The Delog process is executed as an on-demand process by the Storage System Manger, or can be
executed as a command line utility. If Delog is to be initiated from the Storage System Manager, the
Delog process will execute on the same node as the Storage System Manager. If Delog is initiated
from the command line utility, the central log file must be accessible from the node on which the
command is being executed (e.g., NFS mounted). Refer to Section 1.16.2: Viewing the HPSS Log
Messages and Notifications (page 37) in the HPSS Management Guide for detailed information on
Delog.
If a Mover is being run in the non-DCE mode (where the processes that perform the device
management and data transfers run on a different node from the processes that handle the
configuration and managements interfaces), all Mover logging services will be directed to the Log
Client running on the node on which the Mover DCE/Encina process runs.
2.6.12 Metadata Monitor
The primary function of the Metadata Monitor is to periodically collect statistics on the amount of
space used by SFS and notify SSM whenever the percentage of space used exceeds various
thresholds.
A single Metadata Monitor server monitors one and only one Encina SFS server. If multiple Encina
SFS servers are used in an HPSS configuration, multiple Metadata Monitor servers should also be
defined (one per Encina SFS server). A Metadata Monitor server does not necessarily have to
execute on the same machine as the Encina SFS server it monitors.
2.6.13 NFS Daemons
By default files and directories created with NFSwill have their HPSS accountindex set to the user's
default account index. Account validation is recommended with NFS if consistency of accounting
information is desired. If account validation is not enabled, it may not be possible to keep
accounting information consistent. For example, if users have no DCE account, their UID will be
used as the account. This may conflict with users set up to use site style accounting in the same cell.