The following output (from a Vagrant VM running CentOS 6.6) mostly speaks for itself:
[root@localhost ~]# echo 131072 > /proc/sys/fs/inode-max -bash: /proc/sys/fs/inode-max: No such file or directory [root@localhost ~]# sysctl -q -p [root@localhost ~]# echo 'fs.inode-max = 131072' >> /etc/sysctl.conf [root@localhost ~]# sysctl -q -p error: "fs.inode-max" is an unknown key [root@localhost ~]# man proc | col -b | grep -A6 '/proc/sys/fs/inode-max$' /proc/sys/fs/inode-max This file contains the maximum number of in-memory inodes. On some (2.4) systems, it may not be present. This value should be 3-4 times larger than the value in file-max, since stdin, stdout and network sockets also need an inode to handle them. When you regularly run out of inodes, you need to increase this value. [root@localhost ~]# uname -a Linux localhost.localdomain 2.6.32-504.el6.x86_64 #1 SMP Wed Oct 15 04:27:16 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux [root@localhost ~]#
How to reconcile the man page statement that implies this won't exist on 2.4 kernels, with the fact that it doesn't exist on this 2.6 kernel?