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

Managing Filesets
Open System Services Management and Operations Guide—527191-005
5-3
Creating a Unique Fileset
in which file creation, deletion, or opens are a relatively common
occurrence is a a good candidate for the BUFFERED LOG option.
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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.
The fileset becomes inaccessible until it is stopped, repaired using the
SCF DIAGNOSE FILESET command (see Checking and Repairing
Fileset Integrity on page 5-24), and restarted.
•
Fileset recovery information is not recorded in the PXLOG catalog file
(see FSCK Log File on page 5-25).
•
After a double failure of an OSS name server, when the OSS Monitor
attempts to remount a fast-create fileset, the remount request is
rejected by the OSS name server. However, the OSS Monitor
automatically runs the FSCK utility against the fileset and then retries
the remount.
HP recommends that you have a fast-create fileset named TEMP mounted on
/tmp. /tmp should be secured so that all users have read, write, and execute
or search permission, but only the file owner or the super ID can delete
directories or files from the fileset; use this command at an OSS shell prompt:
/bin/chmod 1777 /tmp
•
Specify a processor for the FSCK utility. This action allows you to spread fileset
recovery after a system failure and reload across many processors so that
filesets can be repaired in parallel. That practice allows for faster recovery and
improves the availability of the OSS file system.
Figure 5-1 on page 5-4 shows the relationships created among the configuration
files, processes, and disk volumes by using the SCF ADD FILESET command.
The figure illustrates the effects of this command:
ADD FILESET $ZPMON.MINE, CATALOG $CAT, POOL ZOSSMYPL, &
MNTPOINT "/mine", BUFFERED LOG, NAMESERVER #ZPNS1, &