Configurable parameters related to file system performance
fall into the following categories.
See also “How to Specify Configurable
Parameter Values”.
File
System Buffer Parameter Summary |
 |
Allocate system physical memory resources for static and dynamic
file system buffer cache space. For more information, see “File System Buffer
Parameters”.
File System: Buffer | bufpages | Number of 4 KB pages in file system static
buffer cache. Manpage: bufpages(5). |
File System: Buffer | dbc_max_pct | Maximum percentage of memory for dynamic
buffer cache. Manpage: dbc_max_pct(5). |
File System: Buffer | dbc_min_pct | Minimum percentage of memory for dynamic
buffer cache. Manpage: dbc_min_pct(5). |
File System: Buffer | disksort_seconds | Maximum wait time for disk requests.
NO MANPAGE. |
File System: Buffer | nbuf | System-wide number of static file system
buffer and cache buffer headers. Manpage: nbuf(5). |
Journaled
File Systems (VxFS) Parameter Summary |
|
Allocate space for the Directory Name Lookup Cache (DNLC)
associated with VxFS file system inodes.
File System: Journaled | vxfs_max_ra_kbytes | Maximum amount of read-ahead data, in
KB, that the kernel may have outstanding for a single VxFS file system.
Manpage: vxfs_max_ra_kbytes(5). |
File System: Journaled | vxfs_ra_per_disk | Maximum amount of VxFS file system read-ahead
per disk, in KB. Manpage: vxfs_ra_per_disk(5). |
File System: Journaled | vx_fancyra_enable | Enable or disable VxFS file system read-ahead.
NO MANPAGE. |
File System: Journaled | vx_maxlink | Number of subdirectories created within
a directory. NO MANPAGE. |
File System: Journaled | vx_ncsize | Memory space reserved for VxFS directory
path name cache. Manpage: vx_ncsize(5). |
File System: Journaled | vx_ninode | Number of entries in the VxFS inode table.
NO MANPAGE. |
Logical
Volume Manager (LVM) Parameter Summary |
|
Control kernel interaction with the Logical Volume Manager.
For more information, see “Logical Volume Manager
(LVM) Operation”.
File System: LVM | maxvgs | Maximum number of volume groups configured
by the Logical Volume Manager on the system. Manpage: maxvgs(5). |
Open
or Locked Files Parameter Summary |
|
Set number of files that can be open or locked simultaneously.
For more information, see “Open or Locked Files
Parameters”.
File System: Open/Lock | maxfiles | Soft limit on how many files a single
process can have opened or locked at any given time. Manpage: maxfiles(5). |
File System: Open/Lock | maxfiles_lim | Hard limit on how many files a single
process can have opened or locked at any given time. Manpage: maxfiles_lim(5). |
File System: Open/Lock | ncsize | Inode space needed for directory name
lookup cache (DNLC). NO MANPAGE. |
File System: Open/Lock | nfile | Maximum number of files that can be open
simultaneously on the system at any given time. Manpage: nfile(5). |
File System: Open/Lock | nflocks | Maximum combined number of file locks
that are available system-wide to all processes at one time. Manpage: nflocks(5). |
File System: Open/Lock | ninode | Maximum number of open inodes that can
be in memory. Manpage: ninode(5). |
Disk
Read-Ahead Parameter Summary |
|
Control the amount of memory available for disk read-ahead
operations.
File System: Read | hfs_max_ra_blocks | The maximum number of read-ahead blocks
that the kernel may have outstanding for a single HFS file system. Manpage: hfs_max_ra_blocks(5). |
File System: Read | hfs_max_revra_blocks | The maximum number of reverse read-ahead
blocks that the kernel may have outstanding for a single HFS file system.
Manpage: hfs_max_revra_blocks(5). |
File System: Read | hfs_ra_per_disk | The amount of HFS file system read-ahead
per disk drive, in KB. Manpage: hfs_ra_per_disk(5). |
File System: Read | hfs_revra_per_disk | The amount of memory (in KB) for HFS
reverse read-ahead operations, per disk drive. Manpage: hfs_revra_per_disk(5). |
File System: Read | hp_hfs_mtra_enabled | Enable or disable HFS multithreaded read-ahead.
NO MANPAGE. |
File System: Read | vxfs_max_ra_kbytes | Maximum amount of read-ahead data, in
KB, that the kernel may have outstanding for a single VxFS file system.
Manpage: vxfs_max_ra_kbytes(5). |
File System: Read | vxfs_ra_per_disk | Maximum amount of VxFS file system read-ahead
per disk, in KB. Manpage: vxfs_ra_per_disk(5). |
SCSI
Devices Parameter Summary |
|
Control SCSI device access.
File System: SCSI | scsi_maxphys | Maximum record size for the SCSI I/O
subsystem, in bytes. Manpage: scsi_maxphys(5). |
File System: SCSI | scsi_max_qdepth | Maximum number of SCSI commands queued
up for SCSI devices. Manpage: scsi_max_qdepth(5). |
File System: SCSI | st_ats_enabled | Flag whether to reserve a tape device
on open. Manpage: st_ats_enabled(5). |
File System: SCSI | st_fail_overruns | SCSI tape read resulting in data overrun
causes failure. Manpage: st_fail_overruns(5). |
File System: SCSI | st_large_recs | Enable large record support for SCSI
tape. Manpage: st_large_recs(5). |
Asynchronous
Writes Parameter Summary |
|
Control asynchronous writes to file system.
File System: Write | fs_async | Enable/disable asynchronous writes of
file system data structures to disk. Manpage: fs_async(5). |
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