HP Integrity NonStop H-Series - Manual (Page 42)

Introduction to DSM/SCM
DSM/SCM User’s Guide — 529846-014
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Managing the SYSnn Subvolumes
Managing the SYSnn Subvolumes
DSM/SCM creates a new operating system image, if needed during the Build request.
For software updates that do not require system generation, you can use the current
SYSnn. When system generation is required for an RVU or SPR, you must specify a
new SYSnn. However, you should minimize the number of SYSnn subvolumes on
each target. DSM/SCM requires only one SYSnn in order to operate. If you need to
back out to a previous revision, you need the previous SYSnn if the previous revision
was not on the current SYSnn.
File Types Supported
DSM/SCM supports both Guardian and OSS file types along with the format 2 files <
2GB.
Guardian File Types Supported
All Guardian files are always accessible to all logical targets.
OSS File Types Supported
DSM/SCM supports the management of these OSS file types:

Directories

Hard and symbolic links

Regular files (disk files)

FIFOs
You can configure DSM/SCM to manage OSS files. DSM/SCM requires that all OSS
products contain an A7CINFO file. If you do not configure DSM/SCM to manage OSS
files, you must use COPYOSS and PINSTALL. Use COPYOSS and PINSTALL only if
some OSS products are not DSM/SCM-enabled. You must use COPYOSS for those
files, but you can use DSM/SCM to manage everything else.
For DSM/SCM, a physical target system might have more than one OSS hierarchy, but
only one OSS hierarchy can run and be accessible at a time. An OSS hierarchy must
be running for DSM/SCM to manage the OSS files in it. For an OSS hierarchy to run,
the $SYSTEM volume on which ZXOSSMON exists must be the system load volume
that is currently running.
Caution. Do not use COPYOSS to install OSS files that DSM/SCM manages. Doing so
replaces the DSM/SCM-managed files, which can make it difficult to determine whether OSS
files are managed by DSM/SCM. This confusion can cause problems in managing OSS files
with DSM/SCM.