:: How to check semaphores

ipcs -a

------ Shared Memory Segments --------
key        shmid      owner      perms      bytes      nattch     status

------ Semaphore Arrays --------
key        semid      owner      perms      nsems
0x00000000 65536      daemon     600        1
0x00000000 98305      daemon     600        1

------ Message Queues --------
key        msqid      owner      perms      used-bytes   messages    

 
:: How to check the value of semaphores on Linux

/sbin/sysctl -a | grep sem
kernel.sem = 250	256000	32	1024

 
:: How to increase semaphores on Linux
+ Live and temporary (gone after reboot)

sysctl -w kernel.sem=500
kernel.sem = 500

/sbin/sysctl -a | grep sem
kernel.sem = 500	256000	32	1024

+ Persist

vi /etc/sysctl.conf
## add this line
kernel.sem = 500 256000 32 1024

 
:: Links
+ Google
+ GNUFreakZ

Hi, I’m Sysadmin.ID

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