JFS Tuning and Performance

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Patches
Performance problems are often resolved by patches to the VxFS subsystem, such as the patches for
the VxFS read ahead issues on HP-UX 11i v3. Be sure to check the latest patches for fixes to various
performance related problems.
Summary
There is no single set of values for the tunable to apply to every system. You must understand how
your application accesses data in the file system to decide which options and tunables can be
changed to maximize the performance of your file system. A list of VxFS tunables and options
discussed in this paper are summarized below.
Table 6. List of VxFS tunables and options
newfs
mkfs
Mount
Option
File system
tunables
System wide
tunables
per-file attributes
bsize
logsize
version
blkclear
datainlog
nodatainlog
mincache
convosync
cio
remount
tmplog
delaylog
log
logiosize
tranflush
noatime
nomtime
qio
read_pref_io
read_nstream
read_ahead
write_pref_io
write_nstream
max_buf_data_size
max_direct_iosz
discovered_direct_iosz
max_diskq
write_throttle
initial_extent_size
max_seqio_extent_size
qio_cache_enable
nbuf
bufpages
dbc_max_pct
dbc_min_pct
filecache_min
filecache_max
fcache_fb_policy
vxfs_bc_bufhwm
vx_ninode
vxfs_ifree_timelag
VX_SETCACHE
VX_SETEXT