Proc/Loadavg; Proc/Locks; Proc/Mdstat - Red Hat ENTERPRISE LINUX 5 - DEPLOYMENT Deployment Manual

Chapter 3. The proc File System

3.2.16. /proc/loadavg

This file provides a look at the load average in regard to both the CPU and IO over time, as well as
additional data used by uptime and other commands. A sample /proc/loadavg file looks similar to
the following:
0.20 0.18 0.12 1/80 11206
The first three columns measure CPU and IO utilization of the last one, five, and 15 minute periods.
The fourth column shows the number of currently running processes and the total number of
processes. The last column displays the last process ID used.
In addition, load average also refers to the number of processes ready to run (i.e. in the run queue,
waiting for a CPU share.

3.2.17. /proc/locks

This file displays the files currently locked by the kernel. The contents of this file contain internal kernel
debugging data and can vary tremendously, depending on the use of the system. A sample /proc/
locks file for a lightly loaded system looks similar to the following:
1: POSIX ADVISORY WRITE 3568 fd:00:2531452 0 EOF
2: FLOCK ADVISORY WRITE 3517 fd:00:2531448 0 EOF
3: POSIX ADVISORY WRITE 3452 fd:00:2531442 0 EOF
4: POSIX ADVISORY WRITE 3443 fd:00:2531440 0 EOF
5: POSIX ADVISORY WRITE 3326 fd:00:2531430 0 EOF
6: POSIX ADVISORY WRITE 3175 fd:00:2531425 0 EOF
7: POSIX ADVISORY WRITE 3056 fd:00:2548663 0 EOF
Each lock has its own line which starts with a unique number. The second column refers to the class
of lock used, with FLOCK signifying the older-style UNIX file locks from a flock system call and
POSIX representing the newer POSIX locks from the lockf system call.
The third column can have two values: ADVISORY or MANDATORY. ADVISORY means that the lock
does not prevent other people from accessing the data; it only prevents other attempts to lock it.
MANDATORY means that no other access to the data is permitted while the lock is held. The fourth
column reveals whether the lock is allowing the holder READ or WRITE access to the file. The fifth
column shows the ID of the process holding the lock. The sixth column shows the ID of the file being
locked, in the format of MAJOR-DEVICE:MINOR-DEVICE:INODE-NUMBER. The seventh and eighth
column shows the start and end of the file's locked region.

3.2.18. /proc/mdstat

This file contains the current information for multiple-disk, RAID configurations. If the system does not
contain such a configuration, then /proc/mdstat looks similar to the following:
Personalities : read_ahead not set unused devices: <none>
This file remains in the same state as seen above unless a software RAID or md device is present. In
that case, view /proc/mdstat to find the current status of mdX RAID devices.
24