hfs_revra_per_disk(5)hfs_revra_per_disk(5)NAMEhfs_revra_per_disk - maximum HFS file system blocks to be read in one
read-ahead operation when sequentially reading backwards
This tunable defines the maximum number of file system blocks to be
read in one read-ahead operation when sequentially reading backwards.
Who Is Expected to Change This Tunable?
HP Field engineers, but not customers directly.
When Should the Value of This Tunable Be Raised?
The value of this tunable should be increased if there is a large num‐
ber of reverse sequential file I/O on file systems with small file sys‐
tem block size.
What Are the Side Effects of Raising the Value?
The system will consume more memory in the buffer cache.
When Should the Value of This Tunable Be Lowered?
The value of this tunable should be lowered when there is a smaller
number of reverse sequential file I/O on files systems with large file
system block size.
What Are the Side Effects of Lowering the Value?
The file throughput rate will be decreased.
What Other Tunables Should Be Changed at the Same Time?
All HP-UX kernel tunable parameters are release specific. This parame‐
ter may be removed or have its meaning changed in future releases of
Installation of optional kernel software, from HP or other vendors, may
cause changes to tunable parameter values. After installation, some
tunable parameters may no longer be at the default or recommended val‐
ues. For information about the effects of installation on tunable val‐
ues, consult the documentation for the kernel software being installed.
For information about optional kernel software that was factory
installed on your system, see at
was developed by HP.
Tunable Kernel Parameters hfs_revra_per_disk(5)