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

3-7

OSS File Components

Each OSS data file, or regular file, consists of two components:

•

The catalog portion, which is recorded in an OSS name server catalog file. This

portion supplies structural information about the file.

•

The data portion, which is stored in a file that is identified by a Guardian filename.

This portion contains the data seen by end users of the file.

The Guardian filename is mapped from the OSS pathname using an OSS name server

catalog so that the NonStop operating system disk process can find the data file.

Directories, terminal device files, AF_UNIX sockets, and FIFOs do not have underlying

data files. All information about these files is contained in the catalog.

OSS Catalog Files

The OSS name servers use catalog files to maintain and manage fileset information.

The catalog files maintained by an OSS name server for each fileset contain:

•

Information about the hierarchical directory structure of the fileset.

•

Unique identifiers for the files, called inode numbers in OSS and UNIX terminology

or file serial numbers in POSIX terminology. Each file in the OSS file system has

such an identifier.

The OSS catalog files enable the hierarchical OSS file system to be mapped into the

flat Guardian file system. The catalog files include PXINODE, PXLINK, PXLOG, and

any files saved as described in Generated Catalog Files on page 5-33. All catalog files:

•

Reside in the Guardian environment

•

Are always stored in Guardian subvolumes whose names begin with the letters ZX.

•

Have a Guardian file code of 444 and Guardian file access read, write, execute,

and purge permissions that display as ----.

OSS Data Files

The name of each data file in the OSS file system is mapped into a Guardian filename

with the form \node.$volume.subvol.file-id. The file identifier is the Guardian

representation of the inode for the actual file that contains data usable in the OSS

environment—the OSS regular file.

All OSS regular files:

•

Are always stored in Guardian subvolumes whose names begin with the letters

ZYQ.

•

Have a Guardian file code of 100 and Guardian file access read, write, execute,

and purge permissions that display as ####.