Common Misconfigured HP-UX Resources (April 2006)

If you are using JFS 3.5 and above, you can use the vxfsstat command to display the maximum

number of inodes in the inode cache as follows:

# vxfsstat / | grep inodes

3087 inodes current 128002 peak 128000 maximum

255019 inodes alloced 251932 freed

# vxfsstat -v / | grep maxino

vxi_icache_maxino 128000 vxi_icache_peakino 128002

Note that in the previous example the inode cache can handle a maximum of 128,000 inodes.

Determining the Current Number of Inodes in the JFS Inode Cache

Determining how many inodes are currently in the inode cache is difficult on JFS versions prior to JFS

3.5 as existing user tools do not give this information. You can use the following adb command to

display the current number of inodes in the JFS inode cache if using JFS 3.3:

# echo “vx_cur_inodes/D” | adb –k /stand/vmunix /dev/mem

Using JFS 3.5 and above, you can use the vxfsstat command to display the current number of

inodes in the inode cache as follows:

# vxfsstat / | grep inodes

3087 inodes current 128002 peak 128000 maximum

255019 inodes alloced 251932 freed

# vxfsstat -v /

vxi_icache_curino 3087 vxi_icache_inuseino 635

| grep curino

Note from the previous output that the current number of inodes in the cache is 3087.

Determining the Number of Active JFS Inodes in Use

While a number of the JFS inodes exist in the cache, remember that not all of the inodes are actually

in use as inactive inodes exist in the cache.

For JFS 3.3, there is no easy method to determine the actual inodes in use. For JFS 3.5 and above,

we can again use vxfsstat to determine the actual number of JFS inodes that are in use:

# vxfsstat -v / | grep inuse

vxi_icache_curino 128001 vxi_icache_inuseino 635

The inode cache is filled with 128,001 inodes but only 635 are in use. The remaining inodes are

inactive, and if they remain inactive one of the vxfsd daemon threads will start freeing the inodes

after a certain period of time.

Note that the current number of inodes (128,001) is greater than the maximum number of inodes

(128,000). This behavior is normal as there are few exceptions that allow allocating a few additional

inodes in the cache.

The Inode Free Lists

When a file is not accessed or closed, it is placed on one of many free lists. The free lists store

inodes that can be readily reused. To avoid lock contention when maintaining the free lists, there are

actually many free list headers. The diagram below illustrates this concept: