HP-UX HB v13.00 Ch-14 - JFS

HP-UX Handbook – Rev 13.00 Page 17 (of 47)
Chapter 14 Journaled File System (JFS)
October 29, 2013
The following is an example tunefstab file:
/dev/vx/dsk/userdg/netbackup
read_pref_io=128k,write_pref_io=128k,read_nstream=4,write_nstream=4
/dev/vx/dsk/userdg/metasave
read_pref_io=128k,write_pref_io=128k,read_nstream=4,write_nstream=4
/dev/vx/dsk/userdg/solbuild
read_pref_io=64k,write_pref_io=64k,read_nstream=4,write_nstream=4
/dev/vx/dsk/userdg/solrelease
read_pref_io=64k,write_pref_io=64k,read_nstream=4,write_nstream=4
/dev/vx/dsk/userdg/solpatch
read_pref_io=128k,write_pref_io=128k,read_nstream=4,write_nstream=4
Tunable VxFS I/O parameters
1) print the tuning parameters for all file systems specified on the command line:
# vxtunefs –p [{<mountpoint>|<block-special>}]
2) setting of new parameters for the file system:
# vxtunefs –s –o <parameter=value> [{<mountpoint>|<block-special>}]
-s = sets the parameter
Parameters
read_pref_io
The preferred read request size. The file system uses this in conjunction with the read_nstream
value to determine how much data to read ahead.
The default value is 64K.
write_pref_io
The preferred write request size. The file system uses this in conjunction with the write_nstream
value to determine how to do flush behind on writes.
The default value is 64K.
read_nstream