Linux

Linux OS Materials

How to do tape device discovery for NetBackup device configuration from RHEL Linux command line

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How-To Steps: Scan and discover SCSI devices in Linux cli: scsi-rescan OR: ls -l /sys/class/scsi_host/echo “- – -” > /sys/class/scsi_host/host0/scanecho “- – -” > /sys/class/scsi_host/host1/scanecho “- – -” > /sys/class/scsi_host/host2/scanecho “- – -” > /sys/class/scsi_host/host3/scanecho “- – -” > /sys/class/scsi_host/host4/scanecho “- – -” > /sys/class/scsi_host/host5/scanecho “- – -” > /sys/class/scsi_host/host6/scan The commands to scan and … Read more

Recovering rebooted or crashed GlusterFS

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checking glusterfs configurations: [root@glustertest1 ~]# gluster volume info Volume Name: test_volType: DisperseVolume ID: b23f6c11-8dfe-4d51-919d-35a30dd75100Status: StoppedSnapshot Count: 0Number of Bricks: 1 x (4 + 2) = 6Transport-type: tcpBricks:Brick1: glustertest1:/glusterfs/brick1Brick2: glustertest2:/glusterfs/brick1Brick3: glustertest3:/glusterfs/brick1Brick4: glustertest4:/glusterfs/brick1Brick5: glustertest5:/glusterfs/brick1Brick6: glustertest6:/glusterfs/brick1Options Reconfigured:transport.address-family: inetnfs.disable: on[root@glustertest1 ~]# [root@glustertest1 ~]# gluster volume statusVolume test_vol is not started if its not started: mount glusterFS: [root@glustertest1 ~]# mount … Read more

Rename a GlusterFS Peer in RHEL

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Here are the steps:FYI, its not required to detach the peer. WARNING: Before proceed be sure of backup your data, and proceed with caution. Do not execute any command without understanding what it do exactly, be sure that you are in the correct path, make the correct names replacements in each command if apply (indicated … Read more

Install VectorWise DB on RHEL/CENTOS

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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

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### 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

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### 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

Public Yum Server for Oracle Linux 6,7

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There is no yum repository in Oracle Linux after installation, so it’s necessary to set it in order to update the system with yum command. Oracle provides public yum server and we can use it for free to set. ⇒ Public Yum Server : http://public-yum.oracle.com/ ### Download repository file [root@testos ~]# cd /etc/yum.repos.d/ ### Oracle … Read more

Adjusting VMware ESX host Time Zone(and DST)

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Details: During installation, a time zone was selected for an ESX host that does not match the desired time zone. This article provides steps to change the time zone or daylight-saving. Note: An ESX host with an incorrect date and time or time zone passes on that incorrect information. When a virtual machine boots up … Read more

Convert the dmesg timestamps to human-readable format on Linux

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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

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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