CentOS/RHEL usually uses rsyslogd rate-limit mechanism. Below is an example of message logged in /var/log/messages due to rsyslog rate-limiting. Feb 9 10:22:32 localhost rsyslogd: imuxsock lost 432 messages from pid 9832 due to rate-limiting Feb 9 10:22:45 localhost rsyslogd: imuxsock begins to drop messages from pid 9832 due to rate-limiting The rate limitation prevents logging from using excessive levels of system resources and to flood the /var/log/message with unnecessary messages. To … [Read more...] about How To Disable Or Extend System Logging Rate-limit on CentOS/RHEL 6
How To Disable Or Extend System Logging Rate-limit on CentOS/RHEL 7
CentOS/RHEL usually uses rsyslogd rate-limit mechanism. However, CentOS/RHEL 7.x comes with systemd journal integrated to provide the ability to import structured log messages from systemd journal to syslog. The journal messages on the system's /var/log/messages file looks like in the following example: Jul 30 03:29:45 hostname rsyslogd: imjournal: 102776 messages lost due to rate-limiting How can we disable or extend this logging rate limitation feature on CentOS/RHEL 7.x? Disable or … [Read more...] about How To Disable Or Extend System Logging Rate-limit on CentOS/RHEL 7
How to Configure a Fiber-Channel Over Ethernet (FCoE) Interface in CentOS/RHEL
The Setup This configuration uses below OS, Storage and Server Hardware - OS release - "RHEL 7.1" Kernel - 3.8.13-55.1.6.el7.x86_64 Hardware: HP ProLiant BL460c Gen8 Ethernet Interfaces with FCoE capability - 04:00.0 Ethernet controller: Broadcom Corporation BCM57840 NetXtreme II 10/20-Gigabit Ethernet (rev 11) 04:00.1 Ethernet controller: Broadcom Corporation BCM57840 NetXtreme II 10/20-Gigabit Ethernet (rev 11) 04:00.2 Ethernet controller: Broadcom Corporation BCM57840 NetXtreme … [Read more...] about How to Configure a Fiber-Channel Over Ethernet (FCoE) Interface in CentOS/RHEL
How to Configure Early-kdump Support Feature in CentOS/RHEL 8
What is early kdump support? In previous versions of CentOS/RHEL (5/6/7), the kdump service would start very late in the boot sequence. So early crashes information is lost during the booting. Starting CentOS/RHEL 8, a new kdump mechanism called "early kdump support" was introduced to tackle this issue. Early Kdump stores the vmlinuz and initramfs of the crash kernel inside the initramfs of the booting kernel and load them directly into the reserved memory (crashkernel) during early boot … [Read more...] about How to Configure Early-kdump Support Feature in CentOS/RHEL 8
How to Boot into Rescue Mode or Emergency Mode Through Systemd in CentOS/RHEL 7 and 8
This article explains how to bootup CentOS/RHEL 7 and 8 system into rescue mode or emergency mode. In CentOS/RHEL 7 and 8, both rescue mode and emergency mode are systemd targets which replaced the concept of runlevels in previous CentOS/RHEL versions. Rescue mode is equivalent to single user mode and requires the root password. Rescue mode allows you to repair your system in situations when it is unable to complete a regular booting process. Rescue mode will try to mount all local file … [Read more...] about How to Boot into Rescue Mode or Emergency Mode Through Systemd in CentOS/RHEL 7 and 8
How to check rpm package integrity in Linux
Sometimes, after we download an rpm package manually, would need to check the package integrity sha1 (md5) or signature to avoid problems once it's installed or during the installation. Also, we may need to find other package information like vendor, description, summary. This post describes ways to check rpm package integrity as well as package information. Checking rpm package integrity Use the command "rpm -K --nosignature [rpm-file]". For example: # rpm --checksig … [Read more...] about How to check rpm package integrity in Linux
How to Restart Network Services in CentOS/RHEL 8
In CentOS/RHEL 8 the network services scripts are not presented anymore(systemctl start network.service or /etc/init.d/network script). In order to restart the network services follow one of these two options. Using Network Manager Use the systemctl command to restart the NetworkManager service/target as shown below: # systemctl restart NetworkManager Using nmcli Tool Note: Run these commands from the GUI or the console, as the network will disable. # nmcli networking off # nmcli … [Read more...] about How to Restart Network Services in CentOS/RHEL 8
How To Use distro-sync Option With dnf To Upgrade OS (CentOS/RHEL 8)
dnf has a distro-sync option which is used to synchronize installed packages to the latest available versions. It does the necessary upgrades, downgrades or keeps selected installed packages to match the latest version available from any enabled repository. If no package is given, all installed packages are considered. The distro-sync option of DNF is similar to yum's update option. The following is an example of the distro-sync option: # dnf distro-sync Last metadata expiration check: … [Read more...] about How To Use distro-sync Option With dnf To Upgrade OS (CentOS/RHEL 8)
Real-time SQL Monitoring for Developers – Oracle Database 19c New Feature
The real-time SQL monitoring is an 11g new feature that enables DBAs to monitor the performance of SQL statements while they are executing, Please refer the following post for details. Understanding Real-Time SQL Monitoring in Oracle 11g Beginners Guide to Monitoring SQL Statements with Real-Time SQL Monitoring in Oracle Database Because a primary job duty of database developers is to write and tune SQL statements, starting in Oracle Database 19c, Oracle allows database user to view their … [Read more...] about Real-time SQL Monitoring for Developers – Oracle Database 19c New Feature
Beginners Guide to Monitoring SQL Statements with Real-Time SQL Monitoring in Oracle Database
The post explains how to use Real-Time SQL Monitoring to monitor queries. The Oracle 11g Database or later versions have a new interface to monitor long-running SQL commands. The feature is called Real-Time SQL Monitoring. By default, SQL monitoring is automatically started when a SQL command runs parallel, or when it has consumed at least five seconds of the CPU or I/O time in a single execution. The MONITOR hint can also be used to turn on SQL Monitoring for a SQL statement. SQL Monitoring … [Read more...] about Beginners Guide to Monitoring SQL Statements with Real-Time SQL Monitoring in Oracle Database