Below are few commands which are frequently used to troubleshoot NFS or io troubleshooting check port 2049 and 111 # nmap -p 2049 <nfs_server_ip> -Pn # nc -vz <nfs_server_ip> 2049 # nfsiostat /techbluff # nfsstat -m To get nfsstats of directory and cache every 10 seconds # nfsiostat 10 -d ..
First copy grub file before making changes # cp /etc/default/grub /etc/default/grub-`date +%FT%H%M` Now do required changes in /etc/default/grub # vim /etc/default/grub For Example GRUB_TIMEOUT = 40 After making changes compile grub using grub2-mkconfig # grub2-mkconfig /boot/grub2/grub.cfg # date Sun Mar 19 15:39:28 XXX 2023 # touch te-`date +%FT%H%M` # -rw-r--r-- ..
Search ldap users using below commands # ldapsearch -x -LL uid="<username>" # getent passwd <username> Try to ping or reach the ldap servers(url) which are configured in /etc/ldap.conf # nc -vzw2 ldapserver.techldapuserrs.com 389 Check if ports are open using nmap # nmap -p 389 ldapserver.techldapuserrs.com -PN Do TCP check with traceroute # traceroute ..
There are various tools to find the network cable link of network card connected to a server, however in linux all are files and the connection status can also able be determined by simple cat command. /sys/class which say more # ls -l /sys/class/net/ lrwxrwxrwx 1 root root 0 Aug 11 ..
How do I delete a huge file except last n lines of a file? vi editor has a feature called "ex", By using it you can delete all lines of a file except n lines from a file Create a file with n lines # for i in $(seq 1 2500); do ..
The nscd caches are saved to disk on RedHat system, they are located in /var/db/nscd # ls /var/db/nscd/ group hosts netgroup passwd services When you stop or restart nscd these files just stay there and restarting really wont clear or flush your ..
To find the disk size # fdisk -s /dev/sdb 62914560 In the above command the disk space will be printed in KB. But I had the requirement to print the values in MB or GB for multiple servers. To print diskspace in Megabytes or MB # echo ..
When I tried to run size of my memory, I executed below command and found the result in KB # grep 'MemTotal' /proc/meminfo I can also run free -m or free -g to read the output in MB or GB. But when I have list of values in ..
Normally the agent should be started as a background daemon process. On Windows, this runs as a service. On Linux and Unix systems, the agent starts at boot time from init.d Register rhq-agent-wrapper.sh with chkconfig. # /sbin/chkconfig --add rhq-agent-wrapper.sh Enable the agent service to run at boot time and have it ..
The chown command changes the user ID and/or the group ID of the specified files. Symbolic links named by arguments are silently left unchanged unless -h is used. Changing the owner of a symbolic link needs special attention. When you use chown the regular way to change the owner of a ..
Great things about Ansible is that you dont need to install an Ansible client on the servers you are managing. You only need to install Ansible on your local machine or on a master server that can connect to the managed servers via SSH. Ansible works by configuring client machines ..
When you want to clean the disk or format the disk dd command will be very handy to use it. Format disk using dd command # dd if=/dev/zero of=/dev/sdb # dd if=/dev/null of=/dev/sdd bs=4096 count=1 This command will clean or wipe the data of your existing disk. Use this command ..
Today when I want to mount my external harddisk I felt uneasy since my Redhat linux does not support nfts partiton. NTFS3G is an open source cross-platform, stable, GPL licensed, POSIX, NTFS R/W driver used in Linux. It provides safe handling of Windows NTFS file systems. To proceed with mounting ..
How to yum download a package without installing? Install downloadonly plugin for download option # yum install yum-utils # yum install yum-plugin-downloadonly How to yum download a package? # yum install --downloadonly --downloaddir=<directory> <package> Example: # yum install --downloadonly --downloaddir=./ kmod-VirtualBox-3.19.5-200.fc21.x86_64.x86_64 To download already installed packages # yumdownloader <package> ..
How do I find block size of an partition on Linux? # tune2fs -l /dev/sda1 | grep -i 'block size' Block size: 1024 How do I find block size of a filesystem on Linux? # ..