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

Managing Filesets
Open System Services Management and Operations Guide—527191-005
5-17
Changing the Operating Parameters of a Fileset
Changing Fileset Catalog Buffering
The value used for the BUFFERED option can have a dramatic effect on application
performance when there are a lot of calls to OSS file system functions that cause
fileset catalog updates; such calls include: creat(), unlink(), rename(),
chmod(), chown(), mkdir(), and so on. The possible values of the BUFFERED
option are, in order of increasing buffer usage:
DP2BUFFERED
(the same behavior
as legacy OSS file
caching turned off
[OSSCACHING
OFF])
Single DP2 processor failure
System failure (or double DP2
processor failure)
Application processor failure
Application fails with possible
loss of multiple buffered write
requests if failure occurs before
buffered data is written to disk
Application fails with possible
loss of multiple buffered write
requests if failure occurs before
buffered data is written to disk
Application fails with possible
loss of a single write request if
failure occurs during the write
request
OSSBUFFERED
(the same behavior
as legacy OSS file
caching turned on
[OSSCACHING
ON])
Single DP2 processor failure
System failure (or double DP2
processor failure)
Application processor failure
Application fails with possible
loss of multiple buffered write
requests if failure occurs before
buffered data is written to disk
Application fails with possible
loss of multiple buffered write
requests if failure occurs before
buffered data is written to disk
Application fails with possible
loss of multiple buffered write
requests if failure occurs before
buffered data is written to disk
Value When to use it
NONE An OSS name server writes a record in the PXLOG file as part of each fileset
catalog operation. When both processes of a OSS name server process pair
involved in the operation fail, recovering from a partially completed operation is
fast because it is based on the PXLOG file entry.
This option is provides the slowest performance for fileset catalog updates but
provides the fastest recovery from complete OSS name server failure.
Table 5-1. Effects of File I/O Fault-Tolerance Attribute Settings (page2of2)
Setting Scenarios Results