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November 2024
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Linux cluster commands

Linux cluster commands

Checking status of the cluster: # clustat # clustat -m Display status of and exit # clustat -s Display status of and exit # clustat -l Use long format for services

# cman_tool status Show local record of cluster status # cman_tool nodes Show local record of cluster nodes # cman_tool nodes […]

Why we give swap partition in double the size of the RAM?

Why we give swap partition in double the size of the RAM?

It has a meaning and for that we should know memory hierarchy. We have different levels of memory which is useful for processing your data. They are as follows. Processor/CPU registers(Bits in size) L1 Cache(kbs in size) L2 Cache(MBs in size) L3 cache(100s […]

DD command

* Example use of dd command to create an ISO disk image from a CD-ROM: dd if=/dev/cdrom of=/home/sam/myCD.iso bs=2048 conv=sync

*Using dd to wipe an entire disk with random data: dd if=/dev/urandom of=/dev/hda

*Using dd to clone a hard disk to another hard disk: dd if=/dev/ad0 of=/dev/ad1 bs=1M conv=noerror

*Duplicate a disk partition as a […]

LINUX COMPLETE GUIDE WITH SHELL TIPS

SYSTEM

Hardware | Statistics | Users | Limits | Runlevels | root password | Compile kernel | Repair grub | Misc

Running kernel and system information # uname -a # Get the kernel version (and BSD version) # lsb_release -a # Full release info of any LSB distribution # cat /etc/SuSE-release # Get SuSE version […]

EXT3-fs error (device hda3) in start_transaction: Journal has aborted

EXT3-fs error (device hda3) in start_transaction: Journal has aborted

If your system abruptly loses power, or if a RAID card is beginning to fail, you might see an ominous message like this within your logs:

EXT3-fs error (device hda3) in start_transaction: Journal has aborted

Basically, the system is telling you that […]

lv_root: UNEXPECTED INCONSISTENCY fsck MANUALLY

lv_root: UNEXPECTED INCONSISTENCY; RUN fsck MANUALLY

*** An error occured during hte file system check *** Dropping you to a shell;the system will reboot *** when you leave the shell. Give root password for maintenance (or type Control-D to continue):

now what? First of all i would not worry to much about this error, […]

REDHAT 7 NEW LOOK

[gview file=”http://rmohan.com/wp-content/uploads/2014/06/SHARE-Anaheim-2014-v3.pdf”]

maximum-number-of-file-descriptors-rhel-centos

cat /proc/sys/fs/file-max 589420 The output tells us it is set to 589420. The vendor asked for this to be increased to 1639200. We can add change the value immediately by executing: # sysctl -w fs.file-max=1639200 To make this a permanent setting applied everytime the system reboots an edit of /etc/sysctl.conf file is required. Add: fs.file-max […]

LVM Linux

Logical Volume Manager

Page Contents

•Gathering Information •Creating and Moving Volume Groups •?Partition The Disk ?Initialise The Physical Volumes ?Add the PVs to a Volume Group ?Add Logical Volumes to the Volume Group ?Add Filesystems to the Logical Volumes

• •Migrating a Volume Group to Another System •Reducing the Size of a Logical Volume •Extending […]

Repair filesystem” prompt

How to edit /etc/fstab when at Centos/Redhat “Repair filesystem” prompt?

Now system was unable to boot the system because it was reading /etc/fstab file was unable to find the device for it. This can also happen when you have some external hard-drive attached with your linux system and you remove device but forgot to clean […]