Software storage objects
A software storage object starts out as a single directory subtree
in the /opt hierarchy. This portion of the SSO
remains unchanged
in the same location throughout its lifetime on the system, providing
dependable software for network installations.
To keep the files in the SSO unchanged, custom(ADM) makes copies of files that are expected to change (for example, files that need to be configured differently for different users or programs). custom also links certain files to locations outside the SSO where other programs and users expect to find them. Copying and linking these files is called ``configuring the component to a client''. During a standard installation, custom loads an SSO onto the local system, then configures it to the local system. In more complex installation scenarios, custom can also configure an SSO to one or more ``network filesystem clients'', such as a diskless machine.
Whether a file is copied, linked, or both, depends on whether the file is ``SHARED'' or ``CLIENT'', and whether it is ``PUBLIC'' or ``PRIVATE'':
So, once configured to a particular client, an SSO has two parts: the /opt part, which is shared, and the /var/opt part, which is specific to a client. These two parts can loosely be called the program part (/opt) and the data part (/var/opt).
For each SSO in a product, a client can locate the program part locally or remotely, and the data part locally or remotely. The remote part of each SSO can be located on a different server. Also, this separation between program and data allows control over the location of data that must be backed up regularly or preserved during an upgrade.
Once an SSO is configured into a /opt part and a /var/opt part, links make every PUBLIC file's true location transparent to the system.
Both SHARED and CLIENT files may be either PRIVATE or PUBLIC. There is no mutual exclusivity between these attributes. The following table shows the four possible combinations:
----------------------------------------------------- SHARED CLIENT ----------------------------------------------------- PRIVATE These files remain These files are under /opt. They copied to /var/opt are not linked to an for each client. external directory. They are not linked to an external directory. PUBLIC These files remain These files are in /opt and are copied to /var/opt linked to an for each client and external directory. are linked to an external directory.
See also: