Hello @Malrashed Thank you for your update I think my colleague has already shared the answer to your query. In general for host level swap configuration you can refer the below redhat document https://docs.redhat.com/en/documentation/red_hat_enterprise_linux/7/html/storage_administration_guide/ch-swapspace if swap is available on a host in linux, the Kernel can elect to store things in swap at any time. The system does not have to be out of memory for the Kernel place. As an example a significant number of the pages used by an application during its startup phase may only be used for initialisation and then never used again. The system can swap out those pages and free the memory for other applications or even for the disk cache. That being said sometimes running into swap space is un-avoidable unless the swapiness value is set to 0. Cloudera Manager is set to alert on any usage at all. Cloudera officially recommends setting the swapiness value to 1, but this can lead to the Swap Memory alerts that you're experiencing. POSSIBLE SOLUTIONS: There are two options we have. We can raise the warning threshold, or change the swapiness value to 0. It's really up to you, but most customers raise the warning threshold because with newer versions of the Linux kernel, the swappiness value of 0 now means to "never swap" and in Out of Memory (OOM) situations the kernel is more likely to indiscriminately kill important processes needed reclaim RAM. This may be fine on worker nodes but certainly not Master nodes. In order to fix the error you can do one of the following: To Raise the Threshold: 1.) CM => Search for "host_memswap_thresholds" (Host Memory Swapping Thresholds) => Specify for both Warning and Critical and put the following: Warning: 51200 Critical : 102400 The thresholds are specified in pages (256 = 1MB) So for warning the Memory limit = 200 MB and Critical Memory limit = 400 MB To Change Swapiness Value 1.) In order to change the swap space on a running machine you must issue first the following: echo "0" > /proc/sys/vm/swappiness 2.) To make the swap parameter persistent upon a reboot, use the following command: echo "vm.swappiness=0" >> /etc/sysctl.conf (NOTE: Also vi the sysctl.conf file and delete any vm.swappiness=1 entries) 3.) Issue the command: swapoff -a then swapon -a This will turn off swap space completely and get rid of the warnings, then turn swap back on. NOTE : As per the official document [Ref1] Cloudera recommends swapiness to 1 so please check on that in your environment. [Ref1] : https://docs.cloudera.com/cdp-private-cloud-base/7.1.5/managing-clusters/topics/cm-setting-vmswappiness-linux-kernel-parameter.html I hope this helps Please help our community grow. If you found any of the suggestions/solutions provided helped you with solving your issue or answering your question, please take a moment to login and click "Accept as Solution" on one or more of them that helped.
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