Linux View and modify swap memory configuration (resolve zabbix-agent boot error)

Problem

Zabbix-agent to start an error on a single centos6.5:

Cannot allocate shared memory of size 949056: [+] No space left on Devicecannot allocate GKFX memory for collector

Check

# sysctl-A | grep shm    33554432    2097152    4096

Kernel.shmmax maximum size of a single shared memory segment, in units of byte
Kernel.shmall system allocates the maximum value of a shared memory segment, in the page
Kernel.shmmni maximum number of shared memory segments

You can also view it from another command:

# IPCS-l    ------Shared Memory Limits--------    4096    32768      8388608

Max number of segments corresponds to Kernel.shmmni
Max seg Size (Kbytes) corresponds to Kernel.shmmax (33554432/1024 = 32768)
Max Total Shared memory (Kbytes) corresponds to Kernel.shmall (you can calculate the size of the page: 8388608 * 1024/2097152 = 4096)

Solve

The following begins to analyze the problem, through the log can see the zabbix-agent need to swap memory size is 949056, far less than Kernel.shmmax (33554432), so this parameter is not a problem;

Use the following command to see how the swap memory is allocated (for ease of display here is a properly running zabbix-agent host):

# IPCS-m    ------Shared Memory segments--------    key        shmid      owner      perms      bytes      nattch     status          0          Zabbix              365056     6

On this basis, statistics on how much swap memory has been used (back to the problem host):

# Ipcs-m | grep ' ^0x ' ' {print$} ' ' {sum+=$1}end{print sum} '    1805120

1805120, far less than Kernel.shmall (2097152 * 4096), so this parameter is not a problem;

There is only one reason left, and the number is full:

' ^0x ' | WC-L                                               4096

At this time you can see through the ipcs-m which procedures to fill the number, if there is an exception can choose to use IPCRM release, are normal occupancy, choose to increase the maximum number (here to twice times):

# sysctl-w kernel.shmmni=8192

If you want to restart the system, it still works, write this parameter to the configuration file:

#/etc/sysctl.conf    kernel.shmmni=8192

(The other two parameters are modified in the same way)

Over

Linux View and modify swap memory configuration (resolve zabbix-agent boot error)