Hub/Switch Installation Guide

Chapter 7 HPSS User Interface Configuration
454 September 2002 HPSS Installation Guide
Release 4.5, Revision 2
When multiple HDM serversare to be runon thesamemachine, each HDM must have aunique
SharedMemoryKey. HDM servers cannot share memory or logs without serious consequences.
ZapLogName specifies the name of the file used for the zap log. Typically, this will be /var/hpss/
hdm/hdm<id>/hdm_zap_log. Thisfilecontainsarecordof thearchived filesetfilesthatneedto be
destroyed. The file must exist before HDM is started, but can be empty. The size of the file is
unbounded, but typically will be small. This log is very important and should be stored on a
reliable disk.
7.6.3.3.2 filesys.dat File
The filesystem configuration file, filesys.dat, is a text file that defines each aggregate and fileset
HDM manages. If HDMreceives an event relatedto an aggregateor filesetnot listed in the file, the
event will be aborted and the end user will receive an error. The file must be located in the same
directory as config.dat, typically /var/hpss/hdm/hdm<id>.
This fileismaintained byHDM andshould notneed to beeditedbyan administrator. WhenHDM
modifies the file, a copy of the original file is saved using a name like filesys.YYMMDDhhmmss,
where YYMMDDhhmmss gives the date and time that the original file was saved (not the date
when the original filewas first created.) If many changesaremade in a short period of time,HDM
will not save a copy of each file, but rather will save the most recent file in filesys.bak, overwriting
the previous backups in the process. For example, if the system administrator creates a large
number of filesets at 10:00 AM on 4/1/99, when the operation is complete, three files will be
created: a file named filesys.990401100000 containing a copy of the filesys.dat that was in effect
before the new filesets were created; filesys.bak describing all but the last fileset; and filesys.dat
describing all of the filesets.
When HDMisfirststarted, filesys.datmust bepresent.Itisnot possibleto startHDM iffilesys.dat
is empty or does not have the right format. To make a suitable file for starting HDM the first time,
usea texteditorto createafile whosefirstand lastlines areidenticalandcontain thestring "# HDM
filesys.dat version 1". Alternatively, create the file by copying a template file using
commands such as these:
cd /opt/hpss/config/templates
cp hdm_filesys.dat.template /var/hpss/hdm/hdm<id>/filesys.dat
where /var/hpss/hdm/hdm<id> is the directory where filesys.dat is to beplaced.
Although HDMis responsiblefor maintaining filesys.dat,it may occasionallybe necessary for the
administrator to editthe file manually tocorrect problems. This section describes theformatof the
file.
It is not safe to edit the file any time XDSM managed filesets or aggregates are being created or
deleted. Once the file has been edited, HDM must be restarted for the changes to take effect.
Remember, until HDM is restarted, it can overwrite any changes.
Comments may appear in this file, but they will not be preserved when HDM updates the file.
Commentsbegin witha '#'character andcontinue tothe endof theline. HDMrequiresthatthe first
and last lines in the file contain the comment "# HDM filesys.dat version 1". If these lines
are absent or incorrect, HDM assumes the file is corrupt; so be careful not to alter these lines. With
the exception of these two lines, HDM ignores comments.