Open System Services Management and Operations Guide (G06.30+, H06.08+, J06.03+)

3. Add a record for the fileset to the ZOSSFSET file by using the SCF ADD FILESET command.
Select the appropriate settings for the fileset:
• HP suggests that you select a consistent name for the fileset, directory mount point, and
report file filename to make administration of the fileset easier.
• If the fileset is frequently used, consider having it started or restarted automatically after
a system load or processor failure. An automatically started fileset cannot start until all
filesets above it in the OSS directory hierarchy are started, so a fileset with a
DESIREDSTATE of STARTED cannot start if it uses a mount point on a fileset with a
DESIREDSTATE of STOPPED.
• Read the information in “Using Restricted-Access Filesets and File Privileges” (page 228)
and choose whether or not this fileset is to be a restricted-access fileset. Unless you are
creating an unrestricted fileset, you must be logged on to the local system as a user ID
that is a member of the Safeguard SECURITY-PRV-ADMINISTRATOR (SPA) security group
and a member of the super group (255, nnn), but that is not the super ID (255, 255) or
a member of the Safeguard SECURITY-OSS-ADMINISTRATOR (SOA) group.
• Read the information under “Changing Fileset Input/Output Fault Tolerance” (page 153)
and choose a fault-tolerance option for file input/output within the fileset.
• Read the information under “Changing Fileset Catalog Buffering” (page 154) and choose
a buffering option. These options allow you to increase the relative speed of file creation,
deletion, or opens within the fileset at the expense of increasing the probability of needing
to perform a recovery (repair) for the fileset after a failure. Using a memory cache to
buffer open and close catalog file information for the fileset instead of recording each
transaction in a disk file speeds up transaction processing slightly; however, if the cache
is lost before it can be flushed to disk, the true state of the fileset cannot be determined
without performing a recovery on it:
◦ A fileset using the BUFFERED NONE option directly accesses the fileset catalog on
disk without caching any data in memory. This direct access provides the highest
assurance of data integrity for the fileset catalog and is the least likely to require a
recovery. However, BUFFERED NONE provides the slowest access time to the catalog.
A fileset in which file creation, deletion, and opens are infrequent is a good candidate
for the BUFFERED NONE option.
◦ A fileset using the default BUFFERED LOG option provides slightly faster access time
by using memory cache for some open and close catalog file information; the tradeoff
between performance and recovery for such filesets can be adjusted using the
MAXDIRTYINODETIME option. A fileset in which file creation, deletion, or opens are
a relatively common occurrence is a a good candidate for the BUFFERED LOG option.
◦ A fileset using the BUFFERED CREATE (fast-create) option uses memory cache for as
much file creation, open, and close information as possible between updates of the
actual fileset catalog file on disk. This indirect access to the catalog file provides the
fastest access time for the fileset catalog but with reduced assurance of data integrity
for the catalog and the highest probability of requiring a recovery after a failure. A
fileset in which files are constantly created, deleted, and opened is a good candidate
for the BUFFERED CREATE option.
Although using the BUFFERED CREATE option for a fileset provides better performance
than not using it, the following disadvantages exist:
– Fast-create filesets can contain only one disk volume, and the catalog must reside
on that volume.
– If there is a double failure of the disk process serving a fast-create fileset, recently
created files might be permanently lost.
142 Managing Filesets