Open System Services Management and Operations Guide (G06.29+, H06.07+)

Understanding the OSS File System
Open System Services Management and Operations Guide—527191-005
3-10
OSS Configuration Files
current members of a storage pool are sometimes called the creation pool, to contrast
them with all of the disk volumes used by the fileset as a pool for file storage.
Fileset size depends mainly on the type and complexity of the application mix running
on your system. If you are porting an application from another system, you would have
some idea of the application’s requirements and could use that as a basis for
estimating the application’s disk-space requirements on the NonStop system.
OSS Configuration Files
The OSS file system gets configuration information from the ZOSSFSET file and
storage-pool files. You configure the OSS file system by updating these files according
to directions in Section 5, Managing Filesets.
The ZOSSFSET File
The names of all filesets defined on the system and information about the disk storage
they use resides in a file named ZOSSFSET, defined in the Guardian environment. The
ZOSSFSET file is completely described under Configuration Files on page 4-7.
When a fileset is mounted, its OSS name server accesses catalog files in the catalog
volume that you specify for the fileset in the ZOSSFSET configuration file.
Within that catalog volume, the OSS name server for that fileset uses a Guardian
subvolume whose name begins with ZX0. This name is a reserved subvolume name
used only by an OSS name server.
In this subvolume, the OSS name server for the fileset accesses (and creates if
necessary) the catalog files PXINODE, PXLINK, and PXLOG. Thereafter, whenever
someone mounts or remounts a fileset, the OSS name server that manages that fileset
uses these catalog files. Each fileset has a volume, called a catalog volume, that
contains these catalog files and other information about the fileset.
Files in subvolumes whose names begin with ZYQ are subject to special access
restrictions. You cannot access these files from the Guardian environment, and you
cannot create new files in these subvolumes from the Guardian environment.
Storage Pools and Storage-Pool Files
A storage pool is the set of disk volumes on which the OSS data files of a fileset
reside. The storage-pool file is a Guardian EDIT file that determines which disk
volumes of the storage pool can be used for creating new OSS data files that are being
added to the fileset. The disk volumes listed in the storage-pool file can be viewed as
the creation pool, a subset of the entire storage pool used by the fileset. Figure 3-4 on
page 3-12 shows the difference between an OSS storage pool and the contents of the
storage-pool file for the fileset DATA5; the creation pool is enclosed in a rectangle to
indicate that it is the set of disk volumes identified in the storage-pool file.
The OSS name server for a fileset uses the storage-pool file for that fileset to
determine where to create each new OSS data file. When that OSS name server