fstab option

[???_185]

hi~, i am wordering what's the meaning options.
the example is..
/dev/vgtmp2 /trash vxfs log,mincache=dsync,blkclear,nodatainlog,rw,suid 0 2
so, I am look forward the answer~`

[Mel Burslan · Accepted solution]

If you look into the man page of mount_vxfs command you will see the following along with the meanings of other options that you may encounter doen the road:

blkclear
Clears all data extents before allocating them to a file
(requires synchronous zeroing, on disk, of certain newly
allocated extents). This prevents uninitialized data
from being written to a file at the time of a system
crash.


datainlog|nodatainlog
Generally, VxFS does O_SYNC or O_DSYNC writes by logging
the data and the time change to the inode (datainlog).
If the nodatainlog option is used, the logging of
synchronous writes is disabled; O_SYNC writes the data
into the file and updates the inode synchronously before
returning to the user.

Note: The datainlog option is available only with the HP
OnLineJFS product.



log|delaylog|tmplog|nolog
Control intent logging. To maintain file system
integrity after a system failure, logging must be
enabled. In log mode, file system structural changes are
logged to disk before the system call returns to the
application. If the system crashes, fsck_vxfs(1M)
completes logged operations that did not complete.

In delaylog mode, some system calls return before the
intent log is written. The default is delaylog. This
improves the performance of the system, but some changes
are not guaranteed until a short time later when the
intent log is written. This mode approximates
traditional UNIX system guarantees for correctness in
case of system failures.

In tmplog mode, the intent log is almost always delayed.
This improves performance, but recent changes may
disappear if the system crashes. This mode is only
recommended for temporary file systems.

nolog is an alias for tmplog.

mincache=direct|dsync|unbuffered|closesync|tmpcache
Alter the caching behavior of the file system.

The direct value handles any reads without the O_SYNC
flag, or any writes without the O_SYNC flag, VX_DSYNC,
VX_DIRECT, and VX_UNBUFFERED caching advisories, as if
the VX_DIRECT caching advisory was set.

The dsync value handles any writes without the O_SYNC
flag or one of the VX_DIRECT, VX_DSYNC, or VX_UNBUFFERED
caching advisories as if the VX_DSYNC caching advisory
was set.

The unbuffered value handles any reads without the O_SYNC
flag, or any writes without the O_SYNC flag, VX_DSYNC,
VX_DIRECT, and VX_UNBUFFERED caching advisories, as if
the VX_UNBUFFERED caching advisory was set.

The closesync, dsync, unbuffered, and direct values all
cause the equivalent of an fsync(2) to be run when the
file is closed.

The tmpcache value disables delayed extending writes,
trading off integrity for performance. When this option
is chosen, VxFS does not zero out new extents allocated
as files are sequentially written. Uninitialized data
may appear in files being written at the time of a system
crash. See vxfsio(7) for an explanation of VX_DIRECT,
VX_DSYNC, and VX_UNBUFFERED.

Note: mincache=direct, mincache=dsync,
mincache=unbuffered, and mincache=tmpcache are available
only with the HP OnLineJFS product.


I hope this helps. To see all other options available, run command

man 1M mount_vxfs