VERITAS Volume Manager 3.5 Release Notes (5187-1878, December 2002)

VERITAS File System 3.5 (HP OnlineJFS/JFS 3.5) Release Notes
New and Changed Features
Chapter 1
9
New and Changed Features
The VERITAS File System3.5 (HP OnlineJFS/JFS 3.5) release contains the following
new and changed features:
• New and/or Enhanced Tunable Parameters
— hsm_write_prealloc - Preallocates uninitialized space in a managed region of a
file to improve performance when using hierarchical storage management
(HSM) applications with base/full VxFS 3.5.
— read_ahead - Detects complex read-ahead patterns in addition to sequential
reads.
— write_throttle - Alters the number of dirty pages generated before flushing to
disk to take advantage of new disk storage technology.
See the vxtunefs (1M) manual page for specific information.
• VxFS Command Enhancements
The vxdump command now enables backups at the file or directory level. The
vxrestore command now bypasses the system buffer cache when restoring data
(this enhancement is only available in the full VxFS 3.5 version). This allows a
system's buffer cache to remain intact while doing an extensive restore operation
which typically improves system performance. The vxrestore -c option preserves
backwards compatibility by allowing vxrestore to use the buffer cache. Additionally,
the vxfsconvert command has been enhanced to allow updating the disk layout
version to version 4 on a non-mounted filesystem. The
logiosize=size option was
added to the mount command to enhance the performance of storage devices that
employ a read-modify-write feature. To obtain the maximum performance from such
devices, intent log writes can be done in 1024, 2048, or 4096 bytes.
• New I/O Error Handling Policy
The ioerror option was added to the mount command to provide four different ways
to handle system I/O errors. These policies were implemented on base/full VxFS 3.5
in response to evolving storage technology functionality for which a single method of
I/O error processing was no longer sufficient. One major behavior change is to
disable a file system instead of marking inodes bad on disk-this will prevent
inadvertent data loss. See the mount (1M) manual page for more information.
• New Default Intent Log Mode
To increase performance, the mount command delaylog option has replaced the log
option as the default for base/full VxFS 3.5 file systems. See the mount (1M) manual
page for more information.
• New Default File System Block Size
The default block size is now 1024 bytes for all base/full VxFS 3.5 file systems, no
matter how large the file system you create. Previously, the default block size was
increased with larger file systems. You can still select a larger block size using the
mkfs bsize option. See the mkfs (1M) manual page for more information.