created will require approximately 10MB of disk space in a filesystem that should be us ed only for
database home directories and other DB2 home directories (such as the DB2 Administration Server
and Fenced User). This filesystem should be protected by RAID since DB2 may require information
in the database home directory to properly recover a database.
DB2 backups
Full backups of DB2 databases may be larger than the databases themselves. The amount of local
disk space needed for backups will depend largely on the backup strategy.
When using the DB2 to TSM strategy, local disk is not needed to backup DB2 databases. DB2
communicates directly with the TSM API to deliver backup images and archived log files directly to
TSM. This strategy is highly recommended.
3.5.5. System Memory and Disk Space
The following sections discuss recommendations and requirements for disk space, system memory,
and paging space.
3.5.5.1. Operating Syste m Disk Spaces
It is recommended that all operating system logical volumes/partitions be mirrored. This is true of
the HPSS server and Mover nodes. Both AIX and Linux support this type of configuration.
3.5.5.2. System Disk Spa ce Requirements for Runnin g SSM
The SSM Graphical User Interface, hpssgui, and Command Line Interface, hpssadm, have an option
to create session log files. hpssgui records all status bar and popup messages issued during the
session in its log. hpssadm records all prompts, error and informational messages, and requeste d
output (lists, managed objects, configuration structures, etc.) issued dur ing the session in its log. Old
session log files should be removed periodically to avoid filling the file system. This i s typically
done with a cron job. For example, the following command will remove all files from /tmp which
have not been accessed within the previous seven days:
% find /tmp -atime +7 -exec rm {} \;
The creation of the session log files is controlled by the -S option to the hps sgui and hpssadm startup
scripts. See their man pages for details.
3.5.5.3. System Memory a nd Paging Space Requirements
The memory and disk space requirements for the nodes where the HPSS Servers will execute
depends on the configuration of the servers, the nodes that each server will run on, and the amount
of concurrent access they are configured to handle.
At least 2GB of memory is recommended for nodes that will run one or more HPSS servers (and most
likely a DB2 server), excluding the HPSS Movers. More memory is required for systems that run
most of the servers on one node and/or support many concurrent users. The memory available to
HPSS and DB2 servers is critical to providing acceptable response times to end user operat ions. Disk
space requirements are primarily covered by Section 3.5.4: HPSS Metadata Space on page 74 for
DB2 space, and the preceding subsections under Section 3.5.5: System Memory and Disk Space on
page 78 for the individual HPSS servers. Sufficient disk space should be allocated for the paging
space, using recommendations in the system documentation for the amount of memory configured.
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