• Skip to primary navigation
  • Skip to content
  • Skip to primary sidebar

The Geek Diary

HowTos | Basics | Concepts

  • Solaris
    • Solaris 11
    • SVM
    • ZFS
    • Zones
    • LDOMs
    • Hardware
  • Linux
    • CentOS/RHEL 7
    • RHCSA notes
    • SuSE Linux Enterprise
    • Linux Services
  • VCS
    • VxVM
  • Interview Questions
  • oracle
    • ASM
    • mysql
    • RAC
    • oracle 12c
    • Data Guard
  • DevOps
    • Docker
    • Shell Scripting
  • Hadoop
    • Hortonworks HDP
      • HDPCA
    • Cloudera
      • CCA 131

Linux

CentOS / RHEL : How to install a specific version of rpm package using YUM

By admin

Question : How to install a specific rpm package version using yum? Answer : The ask here is to install a specific version of the package when multiple versions are available. By default when you do not specify a version for a package, latest version gets installed. The procedure below requires you to be logged in as root. 1. clean the yum cache directory # yum clean all 2. To install a specific version of a package we must know the available package version in our repository. List … [Read more...] about CentOS / RHEL : How to install a specific version of rpm package using YUM

Filed Under: Linux

CentOS / RHEL : How to remove unused Physical Volume(PV) from Volume Group (VG) in LVM

By admin

To remove any physical volume in a volume group vgreduce command can be used. The vgreduce command shrinks the volume group by removing one or more PVs. We can then either use these free PVS in another VG or remove them from the LVM configuration. Removing the PV 1. Before removing a physical volume from a volume group, you can make sure that the physical volume is not used by any logical volumes by using the pvdisplay command. # pvdisplay /dev/sdb1 -m --- Physical volume --- PV Name … [Read more...] about CentOS / RHEL : How to remove unused Physical Volume(PV) from Volume Group (VG) in LVM

Filed Under: Linux

CentOS / RHEL : How to find kernel parameters used while booting

By admin

The options and arguments supplied while booting RHEL/CentOS kernel can be viewed in the file /proc/cmdline. # cat /proc/cmdline ro root=/dev/mapper/vg_os-lv_os rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=131M@0M rd_LVM_LV=vg_os/lv_os KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet Comparing with the default boot parameters You can compare the /etc/grub.conf file with the /proc/cmdline file to see if the same options are used while booting the kernel. The … [Read more...] about CentOS / RHEL : How to find kernel parameters used while booting

Filed Under: Linux

CentOS / RHEL : How to convert volume group metadata between LVM1 and LVM2

By admin

The volume group metadata contains all the configuration information about the VG. It can be used to recover a deleted or corrupted VG. By default, the system will backup LVM2 automatically when LVM2 metadata has been changed by lvm utility such as lvcreate or vgchange etc. The metadata backup is stored in /etc/lvm/backup directory. To backup the metadata of current system, just copy the files contained in /etc/lvm/backup to another place. Volume group metadata can be converted from LVM1 to … [Read more...] about CentOS / RHEL : How to convert volume group metadata between LVM1 and LVM2

Filed Under: Linux

CentOS / RHEL : How to find free space in a Volume Group in LVM

By admin

Knowing the free space remaining in a volume group is an important piece of information, especially when you want to : 1. add a new volume in the VG 2. add a new PV in the VG 3. extend an existing volume in the VG Method 1 - using vgs command vgs command simply puts the total size of the VG and free space directly. # vgdisplay -v vg_os2 | grep Free Using volume group(s) on command line. Free PE / Size 40672 / 158.88 GiB Total PE / Free PE 143072 / 40672 In … [Read more...] about CentOS / RHEL : How to find free space in a Volume Group in LVM

Filed Under: Linux

CentOS / RHEL : How to find RPM installation date and time

By admin

You can use the following command to display the install date and time of all the packages installed on your system: rpm -qa --last For example : # rpm -qa --last | more aide-0.14-11.el6.x86_64 Tue 22 Aug 2017 12:57:07 AM IST tzdata-java-2017b-1.el6.noarch Tue 22 Aug 2017 12:27:22 AM IST trace-cmd-2.2.4-4.el6.x86_64 Tue 22 Aug 2017 12:27:22 AM IST ql2500-firmware-7.03.00-1.el6_5.noarch Tue 22 Aug 2017 12:27:22 AM … [Read more...] about CentOS / RHEL : How to find RPM installation date and time

Filed Under: Linux

CentOS / RHEL : How to delete a volume group in LVM

By admin

The post describes steps to delete a volume group. Make sure you have unmounted and the mount points and taken prior backup of the mount point if required. 1. Once you have umounted all the mount points, you can remove the LVs associated with them. To do so use the lvremove command : # lvremove -f [vg_name]/[lv_name] 2. To remove the Volume group we have to deactivate it first with vgchange command : # vgchange -an [vg_name] 3. You can remove the VG now. # vgremove [vg_name] 4. To … [Read more...] about CentOS / RHEL : How to delete a volume group in LVM

Filed Under: Linux

CentOS / RHEL : How to activate and mount 2 Volume groups with same names

By admin

Question: How to mount a Volume_Group/Logical Volume on a system that already has a volume group/logical volume mounted with the same Volume Group and Logical Volume Name. Answer : Below is the summary of steps to perform to import new volume group with same name as that of already imported VG. Backup the system. Get the relevant volume group uuids from the system. Change the name of the Volume Group. Activate the Logical Volume Group. Mount the Logical Volume and verify data … [Read more...] about CentOS / RHEL : How to activate and mount 2 Volume groups with same names

Filed Under: Linux

Linux OS service ‘dhcpd’

By admin

Service Name dhcpd Description - The Dynamic Host Configuration Protocol (DHCP), a derivation of the original Bootstrap Protocol (BOOTP), has expanded its usefulness beyond its thin-client origins. Enterprise-level systems often use the DHCP service to centralize the administration of TCP/IP addresses, network masks, hostnames, router and DNS information. - The dhcpd service is run on the DHCP server. Upon booting, DHCP client machines broadcast queries for information which are then … [Read more...] about Linux OS service ‘dhcpd’

Filed Under: Linux, Linux Services

CentOS / RHEL : How to prioritize the devices used for swap partition

By admin

If you check the output of the swapon -s command, you would see the Priority column. The priority column defines the order in which the swap devices are used when required. In our example below the priority -1 is higher than the priority -2 (as the values are in negative). # swapon -s Filename Type Size Used Priority /dev/dm-1 partition 268435452 0 -1 /swapfile file 102396 0 -2 By default when the priorities are assigned as the swap devices are … [Read more...] about CentOS / RHEL : How to prioritize the devices used for swap partition

Filed Under: Linux

  • « Previous Page
  • Page 1
  • …
  • Page 78
  • Page 79
  • Page 80
  • Page 81
  • Page 82
  • …
  • Page 98
  • Next Page »

Primary Sidebar

Recent Posts

  • How to disable firewalld and nftables and use iptables instead in CentOS/RHEL 8
  • How to add an Ethernet connection using nmcli in CentOS/RHEL 7
  • How to set the order to load certain modules in CentOS/RHEL 7 and 8
  • How to configure initrd / initramfs to including kernel modules in CentOS/RHEL
  • How to configure systemd.path to trigger an event when any changes made to a directory
  • Archives
  • Contact Us
  • Copyright

© 2019 · The Geek Diary