System Admin Q & A – XV

Ques 1: – What is Virtualization ?

Ans: – Virtualization (or virtualisation), in computing, is the creation of a virtual (rather than actual) version of something, such as a hardware platform, operating system, a storage device or network resources.

Ques 2: – what are the key features of NFSv4 ?

Ans: – NFSv4 comes with several new features:

Advanced security management
Kerberos
SPKM
LIPKEY
Firewall friendly
Advanced and aggressive cache management
Non Unix compatibility (Windows)
Easy to administer (Replication, migration)
Crash recovery (Client and server sides

Ques 3: – What are the types of hardware virtualization?

Ans: – Full virtualization: Almost complete simulation of the actual hardware to allow software, which typically consists of a guest operating system, to run unmodified Partial virtualization: Some but not all of the target environment is simulated. Some guest programs, therefore, may need modifications to run in this virtual environment.

Paravirtualization: A hardware environment is not simulated; however, the guest programs are executed in their own isolated domains, as if they are running on a separate system. Guest programs need to be specifically modified to run in this environment.

Ques 4: – What are the benefits of virtualization?

Ans: – Virtualization is a creation of virtual machines and to manage them from one place. It allows the resources to be shared with large number of network resources. Virtualization is having lots of benefits and they are as follows:

It helps in saving lots of cost and allows to easily maintaining it, in less cost.
It allows multiple operating systems on one virtualization platform.
It removes the dependency of heavy hardware to run the application.
It provides consolidating servers that are used for crashing of a server purpose
It reduces the amount of space being taken by data centers and company data.

Ques 5: – What is the location of postfix mailserver Queue ?

Ans: -By default, the Postfix mail queues are located in the /var/spool/postfix directory. Each message queue is created as a separate subdirectory within this directory. Each message is stored as a separate file in the subdirectory, using a unique identifier for the filename.

Ques 5: – What is the Difference Between Qemu and KVM ?

Ans: – QEMU : Itis a generic and open source machine emulator and virtualizer. When used as a machine emulator, QEMU can run OS and programs made for one machine (e.g. an ARM board) on a different machine (e.g. your own PC). By using dynamic translation, Qemu achieves very good performance.

KVM (Kernel Virtual Machine ) : KVM is a Linux kernel module that allows a user space program to utilize the hardware virtualization features of various processors.

Ques 6: – What is Content Negotiation ?

Ans: – Content Negotiation refers to the technique Web clients and servers use to select how to present a resource , such as a document , that is available in several different formats.

Ques 7: – What does /etc/skell directory contains?

Ans: – The /etc/skel directory contains files and directories that are automatically copied over to a new user’s home directory when such user is created by the useradd or adduser command.

Ques 8: – What is the difference between /dev/dsk and /dev/rdsk in Solaris ?

Ans: – In Solaris whenever we create a new slice using format command a raw physical slice or a Raw Device will be created which is addressed as /dev/rdsk/c#d#s# where # is the number for slice.

After formatting it with newfs command the slice will be addressed as /dev/dsk/c#d#s# which can now be used for mounting.

eg.

#newfs /dev/rdsk/c0d0s4

#mkdir /oracle
#mount /dev/dsk/c0d0s4 /oracle

After mounting /dev/dsk/c#d#s# is called as Block Device

/dev actually contains logical device names which are links (Shortcuts in windows terminology) to actual physical devices in /devices directory.arate system. Guest programs need to be specifically modified to run in this environment.

Ques 9: – What is sticky bit in Solaris?

Ans: -Sticky Bit is a permission bit that protects the files with in a Directory. If the directory has sticky bit set, a file can only be deleted by the owner of the file, or root. This Prevents a user from deleting other users files from public directories . The sticky bit is displayed as the letter t in the execute field for ‘others’.