Configure DHCP (Dynamic Host Configuration Protocol) Server in RHEL/Centos 7

### Install DHCP Server [root@testos ~]# yum -y install dhcp ### Configure DHCP Server [root@testos ~]# vi /etc/dhcp/dhcpd.conf # create new # specify domain name option domain-name “unixtest.com”; # specify name server’s hostname or IP address option domain-name-servers testos.unixtest.com; # default lease time default-lease-time 600; # max lease time max-lease-time 7200; # this DHCP server … Read more

How To Install and Configure DellEMC PowerPath on Linux (RHEL/CentOS)

NOTICE: Before you start DellEMC powerpath installation and configuration, make sure HBA cards are installed on the server and Fiber channel switches are zoned properly. [root@unixonline ~]# tar -xzf DellEMCPower.LINUX-7.4.0.b201.tar.gz [root@unixonline ~]# ls DellEMCPower.LINUX-7.4.0.00.00-201.OL7.x86_64.rpm DellEMCPower.LINUX-7.4.0.00.00-201.RHEL8.x86_64.rpm DellEMCPower.LINUX-7.4.0.b201.tar.gz DellEMCPower.LINUX-7.4.0.00.00-201.OL8.x86_64.rpm DellEMCPower.LINUX-7.4.0.00.00-201.SLES12SP5.x86_64.rpm DellEMCPower.LINUX-7.4.0.00.00-201.RHEL7.x86_64.rpm DellEMCPower.LINUX-7.4.0.00.00-201.SLES15SP3.x86_64.rpm In this example, DellEMC Powerpath 7 ( DellEMCPower.LINUX-7.4.0.00.00-201.RHEL7.x86_64.rpm ) is installed on Red Hat 7. … Read more

Reset HBA port in Linux

There are several commands available that allow you to reset one or more interconnects in Linux, issue_lip is one and the most recommended command. The following command can be used to find HBA device name.(in this example host1,host2): [root@unixonline ~]# systool -c fc_host -v|egrep “Device =|node_name|port_state|speed” Class Device = “host1” node_name = “0x20000032fff8dce3” port_state = … Read more

Monitoring Swap Usage for Each Process With the top Command

To monitor which process is using swap, you can use the top command:Log in to Advanced shell (bash).Type the following command to enter the top utility: # top [root@unixonline]# top top – 01:10:24 up 230 days, 9:05, 9 users, load average: 0.00, 0.01, 0.05 Tasks: 220 total, 1 running, 219 sleeping, 0 stopped, 0 zombie … Read more

Install VectorWise DB on RHEL/CENTOS

Actian Vector (formerly known as VectorWise) is an SQL relational database management system designed for high performance in analytical database applications. It published record breaking results on the Transaction Processing Performance Council’s TPC-H benchmark for database sizes of 100 GB, 300 GB, 1 TB and 3 TB on non-clustered hardware. For Installing Vectorwise DB, download/Untar vectorwise DB binary file and start … Read more

Install and Configure Chrony server(NTP) for time adjustment in RHEL/Centos

### Install Chrony. [root@testos ~]# yum -y install chrony ### Edit/Update Chrony Configuration file [root@testos ~]# vi /etc/chrony.conf ### line 3: change servers for synchronization #server 0.centos.pool.ntp.org iburst #server 1.centos.pool.ntp.org iburst #server 2.centos.pool.ntp.org iburst #server 3.centos.pool.ntp.org iburst server <NTP1 SERVER ADDRESS> iburst server <NTP2 SERVER ADDRESS> iburst server <NTP3 SERVER ADDRESS> iburst ### line 25: … Read more

Install and Configure NTP server for time adjustment in RHEL/Centos

### Install NTPd. [root@testos ~]# yum -y install ntp ### Edit/Update NTP Configuration file [root@testos ~]# vi /etc/ntp.conf ### line 18: add the network range you allow to receive requests restrict 10.0.0.0 mask 255.255.255.0 nomodify notrap ### change servers for synchronization ### change servers for synchronization #server 0.centos.pool.ntp.org iburst #server 1.centos.pool.ntp.org iburst #server 2.centos.pool.ntp.org iburst … Read more

Convert the dmesg timestamps to human-readable format on Linux

The dmesg results from newer Linux kernels show the timestamps. the dmesg timestamp is the time in seconds since the kernel starting time. [root@unixonline]# dmesg [2593404.865599] vmxnet3 0000:0b:00.0 ens192: intr type 3, mode 0, 5 vectors allocated [2593404.868590] vmxnet3 0000:0b:00.0 ens192: NIC Link is Up 10000 Mbps [2593426.220166] vmxnet3 0000:0b:00.0 ens192: intr type 3, mode … Read more

MySQL Server Time Zone Support

This article describes the time zone settings maintained by MySQL, how to load the system tables required for named time support, how to stay current with time zone changes, and how to enable leap-second support. Beginning with MySQL 8.0, time zone offsets are also supported for inserted datetime values; see “The DATE, DATETIME, and TIMESTAMP Types”, … Read more