Oracle Linux System Stops Responding for a Brief Period Every 10 Minutes
(Doc ID 2904485.1)
Last updated on OCTOBER 28, 2022
Applies to:
Oracle Cloud Infrastructure - Version N/A and laterLinux OS - Version Oracle Linux 7.0 and later
Information in this document applies to any platform.
Symptoms
- Every 10 minutes, multiple operations in Oracle Linux environments seem to stop responding for a small period – this can be seen when executing simple commands like ls, pinging other servers, etc. Other that those slight “freezes” no other errors can be observed and there is no observable increase in general system load.
- It can be seen from /proc/buddyinfo that the system memory is fragmented, with only a small number of higher order memory segments free, e.g.:
In the above example, it can be seen the system has 0 free blocks of the largest order and only 0-1-1 for the next larger order ones. So almost no memory segments larger than 256KB are available.The content of /proc/buddyinfo as shown above show you the number of free memory chunks (see the last line labelled Normal). You have to read the numbers from left to right where the first column is order 0 = 4k, order 1 = 8k, order 2 = 16k, order 3 = 32k, order 4 = 64k, order 5 = 128k, order 6 = 256k, order 7 = 512k, order 8 = 1M, order 9 = 2M, order 10 = 4M. This is for a standard Linux system using 4KB standard memory block size.
The file /proc/buddyinfo is used primarily for diagnosing memory fragmentation issues. Using the buddy algorithm, each column represents the number of pages of a certain order (a certain size) that are available at any given time.
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The system is running OSWatcher.
Cause
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In this Document
Symptoms |
Cause |
Solution |
References |