What is an open file? An open file may be a regular file, a directory, a block special file, a character special file, an executing text reference, a library, a stream or a network file. What is file descriptor? A file descriptor is a data structure used by a program to get a handle on a file. The most commonly known are: 0 for standard in 1 for standard out 2 for standard error Does the number of open files equal the number of open file descriptors? There is a difference in the … [Read more...] about Linux Interview Questions : Open Files / Open File Descriptors
Interview Questions
Linux interview questions – Special permissions (SUID, SGID and sticky bit)
There are two special permissions that can be set on executable files: Set User ID (setuid) and Set Group ID (sgid). These permissions allow the file being executed to be executed with the privileges of the owner or the group. Similarly, there are two special permissions for directories: the sticky bit and the setgid bit. Below are few of the most commonly asked Linux interview questions on the special permissions like SUID, SGID and sticky bit. What is Set User ID (setuid)? SUID is a … [Read more...] about Linux interview questions – Special permissions (SUID, SGID and sticky bit)
Oracle Database interview questions – Privileges And Roles
What is a Privilege? A privilege is the right to execute a particular type of SQL statement. It can allow a user to access database objects or execute stored programs that are owned by another user or to perform system level actions. There are two types of privileges: system privileges schema object privileges What are system privileges? The system privileges are not related to a certain object. They control the ability of a user to perform system level actions such as connecting to … [Read more...] about Oracle Database interview questions – Privileges And Roles
The ultimate Linux interview questions : swap
What is swap space? Swap space in Linux is used when the amount of physical memory (RAM) is full. If the system needs more memory resources and the physical memory is full, inactive pages in memory are moved to the swap space. While swap space can help machines with a small amount of RAM, it should not be considered a replacement for more RAM. Swap space is located on hard drives, which have a slower access time than physical memory. Swap space can be a dedicated swap partition … [Read more...] about The ultimate Linux interview questions : swap
The ultimate Solaris Volume Manager (SVM) interview questions
What are the configuration files used in SVM ? /etc/lvm/md.tab 1. The file is empty by default. The file is only used when metainit command is issued by the administrator. It is configured manually. 2. It can be populated by appending the output of # metastat -p. For example #metastat -p >> /etc/lvm/md.tab. 3. It can be used to recreate all the metadevices in one go. Best used in recovery of SVM configurations. For example # metainit -a (to create all metadevices mentioned in md.tab … [Read more...] about The ultimate Solaris Volume Manager (SVM) interview questions
The ultimate Solaris zones (containers) interview questions
Basics Whats the difference between a whole root zone and a sparse root zone ? Whole root zone - Gets its own writable copy of all file systems. Thus installation takes longer time than the sparse root zone. - Also called as big zone. - Bigger disk footprint, thus consumes more disk space - To create a Whole root zone we use the option -b with create sub-command : # zonecfg -z zone01 zonecfg:zone01> create -b Sparse root zone - critical file systems like /usr, /lib, /etc, … [Read more...] about The ultimate Solaris zones (containers) interview questions
The ultimate Solaris networking interview questions
Basics What are the files required for a persistent IP address configuration ? To be able to have a persistent IP address configuration across reboots, make sure you edited the mentioned file below : /etc/hostname.[interface] -- Add IP address/hostname for interface /etc/netmasks -- add netmasks for the networks being used to configure IP address /etc/hosts -- Add IP address and hostname How to check the routing table ? To list all the routing table entries : # … [Read more...] about The ultimate Solaris networking interview questions
The ultimate Veritas Cluster Server (VCS) interview questions
Basics What are the different service group types ? Service groups can be one of the 3 type : 1. Failover - Service group runs on one system at a time. 2. Parallel - Service group runs on multiple systems simultaneously. 3. Hybrid - Used in replicated data clusters (disaster recovery setups). SG behaves as Failover within the local cluster and Parallel for the remote cluster. Where is the VCS main configuration file located ? The main.cf file contains the configuration of the entire … [Read more...] about The ultimate Veritas Cluster Server (VCS) interview questions
The ultimate ZFS interview questions
How to create a ZFS volume ? The command to create a ZFS volume of 1 GB is : # zfs create -V 1g geekpool/volume01 How to do a dry run before actually creating a ZFS pool ? We can simulate a ZFS operation using the -n option without actually writing to the disk devices. For example, a dry run of zpool creation is : # zpool create -n geekpool mirror c1t0d0 c1t1d0 would create 'geekpool' with the following layout: tank mirror c1t0d0 … [Read more...] about The ultimate ZFS interview questions