HP JFS 3.3 and HP OnLineJFS 3.3 VERITAS File System 3.3 System Administrator's Guide

Chapter 5 101
Performance and Tuning
Kernel Tuneables
Kernel Tuneables
This section describes the kernel tuneables in VxFS.
Internal Inode Table Size
VxFS caches inodes in an inode table (see Table 5-1, “Inode Table
Size”). There is a tuneable in VxFS called vx_ninode that determines
the number of entries in the inode table.
A VxFS file system obtains the value of vx_ninode from the system
configuration file used for making the kernel (/stand/system for
example). This value is used to determine the number of entries in the
VxFS inode table. By default, vx_ninode initializes at zero; the file
system then computes a value based on the system memory size (see
Table 5-1, “Inode Table Size”). To change the computed value of
vx_ninode, you can add an entry to the system configuration file. For
example:
vx_ninode1000000
sets the inode table size to 1,000,000 inodes after making a new kernel
using mk_kernel and then rebooting.
The number of inodes in the inode table is calculated according to the
following table. The first column is the amount of system memory, the
second is the number of inodes. If the available memory is a value
between two entries, the value of vx_ninode is interpolated.
Table 5-1 Inode Table Size
Total Memory in Mbytes Maximum Number of Inodes
8 400
16 1000
32 2500
64 6000
128 8000
256 16,000
512 32,000
1024 64,000
2048 128,000
8192 256,000
32,768 512,000
131,072 1,024,000