Backup Commands in Linux & Unix with Usage and Examples

Unix and Linux backup and restore can be done using backup commands tar, cpio ufsdump, dump and restore. Though these commands may be sufficient for small setups in order to take a enterprise backup you have to go in for some custom backup and restore solutions like Symatic netbackup, EMC networker or Amanda.
Any backup solution using these commands depends on the type of backup you are taking as these backup commands offers different capabilities.
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Unix Tech Tips

  1. Running Sol
    aris  in 32 or 64 bit mode
    – Page 1
  2. Removing ^M from Unix text files – Page 2
  3. Backup commands – ufsdump , tar , cpio – Page 3
  4. Setting up Ethernet card speed & duplex mode – Page 4
  5. One Line scripts – Page 4

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Booting Problems & Solutions in Solaris

Booting problems poses serious challenge to the system administrators as system is down and no one can use it . This article tries to cover some of the general booting problems and their possible solutions to enable understand the problem cause and bring the system up very quickly.

Following are some of the booting issues ,error messages their meaning and possible solutions discussed in this article. Continue reading “Booting Problems & Solutions in Solaris”

Domain Name Service

Domain name server

DNS Server Setup & Configuration in Unix

Domain name services resolves names to the ip addresses of clients and vice verse. Domain name system provides a convenient way of finding computer systems in network based on its name and ip address . With increased internet usage and globalization of companies setting up of DNS servers has become a major responsibility of system administrators worldwide . Continue reading “Domain Name Service”

fsck Command – Check & Repair Linux & Unix File Systems

fsck, similar to chkdsk in windows, checks and repairs the file system in Unix & Linux operating systems. Learn about fsck modes, phases & fsck errors messages

fsck, File System Consistency checK, is a system utility in Unix, Linux and other Unix like systems for checking and repairing file system inconsistencies.

File system can become inconsistent due to several reasons and the most common is abnormal shutdown due to hardware failure, power failure or switching off the system without proper shutdown. Due to these reasons the superblock in a file system is not updated and has mismatched information relating to system data blocks, free blocks and inodes.

fsck in Linux

fsck in this document is refered with reference to ufs file system but it can be used in Linux systems as

fsck -t ext2 /dev/sda3
or
fsck.ext2 /dev/sda3
fsck.ext4 /dev/sda3
fsck.ext3 /dev/sda3

it returns with any of the followig code

0 – No errors
1 – File system errors corrected
2 – System should be rebooted
4 – File system errors left uncorrected
8 – Operational error
16 – Usage or syntax error
32 – Fsck canceled by user request
128 – Shared library error

fsck checks the file systems defined in /etc/fstab in Linux and /etc/vfstab in Unix systems

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Veritas Volume Manager – vxassist

vxassist utility in veritas volume manager is used to create volumes, add mirrors and logs to existing volumes, extend and shrink existing volumes, provides for the migration of data from a specified set of disks, and provides facilities for the on-line back up of existing volumes.
The default behavior of vxassist is to create volumes in the rootdg diskgroup if diskgroup is not specified . The default length is taken as number of blocks but this can be specified in Kilobytes or Megabytes or Gigabytes. Continue reading “Veritas Volume Manager – vxassist”