Veritas File System v5.0.1 Administrator's Guide for HP-UX 11i v3 (5900-0082, June 2010)

support bad block revectoring, then a failure is more likely, so the nodatainlog
mode should be used.
A nodatainlog mode file system is approximately 50 percent slower than a
standard mode VxFS file system for synchronous writes. Other operations are
not affected.
The blkclear mode
The blkclear mode is used in increased data security environments. The blkclear
mode guarantees that uninitialized storage never appears in files. The increased
integrity is provided by clearing extents on disk when they are allocated within
a file. This mode does not affect extending writes. A blkclear mode file system
is approximately 10 percent slower than a standard mode VxFS file system,
depending on the workload.
The mincache mode
The mincache mode has the following suboptions:
■ mincache=closesync
■ mincache=direct
■ mincache=dsync
■ mincache=unbuffered
■ mincache=tmpcache
The mincache=closesync mode is useful in desktop environments where users
are likely to shut off the power on the machine without halting it first. In this
mode, any changes to the file are flushed to disk when the file is closed.
To improve performance, most file systems do not synchronously update data
and inode changes to disk. If the system crashes, files that have been updated
within the past minute are in danger of losing data. With the mincache=closesync
mode, if the system crashes or is switched off, only open files can lose data. A
mincache=closesync mode file system could be approximately 15 percent slower
than a standard mode VxFS file system, depending on the workload.
The following describes where to use the mincache modes:
■ The mincache=direct, mincache=unbuffered, and mincache=dsync modes
are used in environments where applications have reliability problems caused
by the kernel buffering of I/O and delayed flushing of non-synchronous I/O.
VxFS performance: creating, mounting, and tuning file systems
Mounting a VxFS file system
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