Red Hat ENTERPRISE LINUX 5 - DEPLOYMENT Deployment Manual page 70

Chapter 3. The proc File System
• hotplug — Configures the utility to be used when a configuration change is detected by the
system. This is primarily used with USB and Cardbus PCI. The default value of /sbin/hotplug
should not be changed unless testing a new program to fulfill this role.
• modprobe — Sets the location of the program used to load kernel modules. The default value is /
sbin/modprobe which means kmod calls it to load the module when a kernel thread calls kmod.
• msgmax — Sets the maximum size of any message sent from one process to another and is
set to 8192 bytes by default. Be careful when raising this value, as queued messages between
processes are stored in non-swappable kernel memory. Any increase in msgmax would increase
RAM requirements for the system.
• msgmnb — Sets the maximum number of bytes in a single message queue. The default is 16384.
• msgmni — Sets the maximum number of message queue identifiers. The default is 16.
• osrelease — Lists the Linux kernel release number. This file can only be altered by changing the
kernel source and recompiling.
• ostype — Displays the type of operating system. By default, this file is set to Linux, and this value
can only be changed by changing the kernel source and recompiling.
• overflowgid and overflowuid — Defines the fixed group ID and user ID, respectively, for use
with system calls on architectures that only support 16-bit group and user IDs.
• panic — Defines the number of seconds the kernel postpones rebooting when the system
experiences a kernel panic. By default, the value is set to 0, which disables automatic rebooting
after a panic.
• printk — This file controls a variety of settings related to printing or logging error messages. Each
error message reported by the kernel has a loglevel associated with it that defines the importance of
the message. The loglevel values break down in this order:
• 0 — Kernel emergency. The system is unusable.
• 1 — Kernel alert. Action must be taken immediately.
• 2 — Condition of the kernel is considered critical.
• 3 — General kernel error condition.
• 4 — General kernel warning condition.
• 5 — Kernel notice of a normal but significant condition.
• 6 — Kernel informational message.
• 7 — Kernel debug-level messages.
Four values are found in the printk file:
6 4 1 7
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