From be1c7e50e1e8809ea56f2c9d472eccd8ffd73a97 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Fri, 19 Apr 2024 04:57:58 +0200 Subject: Adding upstream version 1.44.3. Signed-off-by: Daniel Baumann --- health/guides/ipc/semaphore_arrays_used.md | 46 ++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 health/guides/ipc/semaphore_arrays_used.md (limited to 'health/guides/ipc/semaphore_arrays_used.md') diff --git a/health/guides/ipc/semaphore_arrays_used.md b/health/guides/ipc/semaphore_arrays_used.md new file mode 100644 index 00000000..d12dacd4 --- /dev/null +++ b/health/guides/ipc/semaphore_arrays_used.md @@ -0,0 +1,46 @@ +### Understand the alert + +This alarm monitors the percentage of used `System V IPC semaphore arrays (sets)`. If you receive this alert, it means that your system has a high utilization of `IPC semaphore arrays`, which can affect application performance. + +### Troubleshoot the alert + +1. Check the current usage of semaphore arrays + + Use the `ipcs -u` command to display a summary of the current usage of semaphore arrays on your system. Look for the "allocated semaphores" section, which indicates the number of semaphore arrays being used. + + ``` + ipcs -u + ``` + +2. Identify processes using semaphore arrays + + Use the `ipcs -s` command to list all active semaphore arrays and their associated process IDs (PIDs). This information can help you identify which processes are using semaphore arrays. + + ``` + ipcs -s + ``` + +3. Investigate and optimize processes using semaphore arrays + + Based on the information from the previous step, investigate the processes that are using semaphore arrays. If any of these processes can be optimized or terminated to free up semaphore arrays, do so carefully after ensuring that they are not critical to your system. + +4. Adjust the semaphore limit on your system + + If the semaphore array usage is still high after optimizing processes, you may need to increase the semaphore limit on your system. As mentioned earlier, you can adjust the limit in the `/proc/sys/kernel/sem` file. + + ``` + vi /proc/sys/kernel/sem + ``` + + Edit the fourth field to increase the max semaphores limit. Save the file and exit. To apply the changes, run: + + ``` + sysctl -p + ``` + + Please note that increasing the limit might consume more system resources. Monitor your system closely to ensure that it remains stable after making these changes. + +### Useful resources + +1. [Interprocess Communication](https://docs.oracle.com/cd/E19455-01/806-4750/6jdqdfltn/index.html) +2. [IPC: Semaphores](https://users.cs.cf.ac.uk/Dave.Marshall/C/node26.html) -- cgit v1.2.3