VERITAS File System 4.1 Administrator's Guide

VxFS Performance: Creating, Mounting, and Tuning File Systems
I/O Tuning
Chapter 2 63
inode_aging_count Specifies the maximum number of inodes to place on an
inode aging list. Inode aging is used in conjunction with file
system Storage Checkpoints to allow quick restoration of
large, recently deleted files. The aging list is maintained in
first-in-first-out (fifo) order up to maximum number of
inodes specified by inode_aging_count. As newer inodes
are placed on the list, older inodes are removed to complete
their aging process. For best performance, it is advisable to
age only a limited number of larger files before completion
of the removal process. The default maximum number of
inodes to age is 2048.
inode_aging_size Specifies the minimum size to qualify a deleted inode for
inode aging. Inode aging is used in conjunction with file
system Storage Checkpoints to allow quick restoration of
large, recently deleted files. For best performance, it is
advisable to age only a limited number of larger files before
completion of the removal process. Setting the size too low
can push larger file inodes out of the aging queue to make
room for newly removed smaller file inodes.
max_direct_iosz The maximum size of a direct I/O request that will be
issued by the file system. If a larger I/O request comes in,
then it is broken up into max_direct_iosz chunks. This
parameter defines how much memory an I/O request can
lock at once, so it should not be set to more than 20 percent
of memory.
max_diskq Limits the maximum disk queue generated by a single file.
When the file system is flushing data for a file and the
number of buffers being flushed exceeds max_diskq,
processes will block until the amount of data being flushed
decreases. Although this doesn't limit the actual disk queue,
it prevents flushing processes from making the system
unresponsive. The default value is 1 MB.