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Due to various circumstances, I wanted to reproduce a situation where I/O stops, so here are my notes on how I reproduced I/O suspension using dmsetup. Reproducing IO Suspension with dmsetup Check status dmsetup info Suspend IO dmsetup suspend /dev/vol01/test Resume IO dmsetup resume /dev/vol01/test Links dmsetup Command Red Hat Enterprise Linux 7 | Red Hat Customer Portal …

Overview I wanted to perform a load test with short packets, so I tried using Pktgen-DPDK. It is necessary to enable IOMMU beforehand. IOMMU Activation Memo Environment Environment Version Ubuntu 22.04 DPDK 23.11.1 Pktgen-DPDK main branch NIC Intel X520 DA2 Installing Required Packages Install dependencies sudo apt-get update sudo apt-get install -y git build-essential libnuma-dev python3-pyelftools linux-headers-$(uname -r) meson ninja-build Building and Installing DPDK Download the DPDK library DPDK Download I chose to use the latest LTS version, 23. …

BIOS Refer to the BIOS manual. Linux Kernel Add the required options at boot time # vi /etc/default/grub GRUB_CMDLINE_LINUX_DEFAULT="amd_iommu=on" For AMD, specify amd_iommu=on, and for Intel, specify intel_iommu=on. Apply GRUB configuration # update-grub Reboot # reboot Verify parameters # cat /proc/cmdline Check dmesg # dmesg | grep iommu …

Notes on using non-Intel SFP+ with Intel X520 DA2 on Linux. Add driver options # cat << _EOF_ > /etc/modprobe.d/ixgbe.conf options ixgbe allow_unsupported_sfp=1,1 _EOF_ Unload and reload the driver # modprobe -r ixgbe # modprobe ixgbe Regenerate initramfs # update-initramfs -u Without this, allow_unsupported_sfp=1,1 will not be enabled on reboot. …

This is a method to cache 502 (Bad Gateway) and 504 (Gateway Timeout) errors using the Sakura Cloud Web Accelerator. High access to non-cacheable content or even cacheable content can cause the origin server to return 502 (Bad Gateway) or 504 (Gateway Timeout) errors due to high server load. Normally, error responses from nginx do not include Cache-Control headers, so they are not cached, which means the load on the origin server continues. …

This document records the setup notes for Rundeck. Environment Version Ubuntu 22.04 Rundeck 4.14.1 Installing Java # apt-get install -y openjdk-11-jre-headless Registering the Repository The official method uses apt-key, which issues a warning on 22.04, so we will change it. # curl -L https://packages.rundeck.com/pagerduty/rundeck/gpgkey > /etc/apt/keyrings/rundeck.asc Next, add the Rundeck repository. # cat << _EOF_ > /etc/apt/sources.list.d/rundeck.list deb [signed-by=/etc/apt/keyrings/rundeck.asc] https://packages.rundeck.com/pagerduty/rundeck/any/ any main deb-src [signed-by=/etc/apt/keyrings/rundeck.asc] https://packages.rundeck.com/pagerduty/rundeck/any/ any main _EOF_ Once the repository is added, update the package information. …

This is a note on setting up Zabbix 6.4. The configuration includes Zabbix + Nginx + php-fpm + PostgreSQL + TimescaleDB. Environment Version Ubuntu 22.04 Zabbix 6.4 PostgreSQL 15 Nginx 1.18.0 php-fpm 8.1.2 Register the Repository Download and install Zabbix # wget https://repo.zabbix.com/zabbix/6.4/ubuntu/pool/main/z/zabbix-release/zabbix-release_6.4-1+ubuntu22.04_all.deb # dpkg -i zabbix-release_6.4-1+ubuntu22.04_all.deb # apt update Install Zabbix # apt install zabbix-server-pgsql zabbix-frontend-php php8.1-pgsql zabbix-nginx-conf zabbix-sql-scripts zabbix-agent Install PostgreSQL # apt install postgresql postgresql-contrib Add PostgreSQL Repository and Install # apt install software-properties-common gnupg postgresql-common apt-transport-https lsb-release wget # /usr/share/postgresql-common/pgdg/apt. …

Here are the notes on installing Metabase on Ubuntu 22.04 LTS. Install Java The Java Development Kit (JDK) is required. apt-get install -y default-jdk Create Metabase Installation Directory install -d /opt/metabase cd /opt/metabase Download Metabase Download the Metabase binary with the following command: wget https://downloads.metabase.com/v0.45.3/metabase.jar Create User and Group useradd metabase -d /opt/metabase chown -R metabase:metabase /opt/metabase Create systemd Service File Create a systemd service file with the following command: …

The Busybox dmesg command lacks the -T option to convert and display timestamps, so I tried converting them with a one-liner. One-liner uptime=$(cut -d. -f1 /proc/uptime); dmesg | while read line; do time=$(echo $line | sed -e 's/^\[ *\([0-9]*\).*$/\1/g'); echo "[$(date -d @$(($(date +%s) - $uptime + $time)))] $(echo $line | cut -d ] -f 2 -)" ; done Brief Explanation /proc/uptime records the elapsed time since the system was started in seconds. …

This guide explains how to set up HTTPS SSL certificates on OpenWrt. Can it actually be configured from the WebUI?? For certificates with a short validity period, such as those from Let’s Encrypt, it might be a good idea to automate the process using a shell script and run it periodically with cron. Prerequisites Obtain an SSL certificate Enable HTTPS from the WebUI System -> Administration -> HTTP(S) Access Check the box for Redirect to HTTPS Convert SSL certificate and private key to DER format openssl x509 -in server. …