Sun Solaris Interview Questions

Solaris is a Unix based operating system that was initially developed by Sun Microsystems. Initially released in 1992, Solaris is written in C and C++. A proprietary software, Solaris is now under Oracle after the acquisition of Sun Microsystems. The Oracle Solaris is known for its scalability on SPARC systems and has support for x86-64 workstations. Oracle Solaris is now considered as the most widely deployed UNIX operating system that provides reliability, performance, and enterprise-class security for mission-critical applications.

Zones in Solaris are used to isolate software applications and services using flexible software-defined boundaries. Previously known as Solaris containers,

You can build the Oracle Solaris Zones using technologies such as Solaris Resource Manager, and Solaris Zones Partitioning technology. Zone creates a virtualized operating system environment that is then represented to the applications as isolated and complete.

Solaris supports six RAID levels from 0 to 6. Only a few storage environments support RAID levels 2, 3, and 4.

The other three RAID levels are most supported by the storage environments.

RAID level 0 - Here, the data are spread across relatively small, equally-sized fragments which are allocated evenly across multiple physical disks.

RAID level 1 - Here, the mirroring technique is used to duplicate the data over two or more physical disks.

RAID level 5 - Here, the striping technique is used to spread the data over the disks in an array. It will have substantial performance degradation when operating with a failed device.

A pipe is a pair of files between two process that is created in the parent process. A pipe is used to connect only two processes and a single pipe also connects multiple child processes to each other and their related parent.

A process can create a pipe with a call to pipe(). This call returns two file descriptors in the array. Both the processes read from p[0] and write to p[1].

The FSCK command in the Solaris used to check and repair inconsistencies in the file system. You can run this command with many options but if you run without any options, it asks for confirmation before making the repair. The options used with this command are '-m', '-y', '-n', '-op'.

The '-m' is used to check if a file system can be mounted, '-y' assumes yes response for all repairs, '-n' assumes no responsibility for all repairs, '-o p' preens the file system and fixes all the inconsistencies.

You can use the command "pkginfo | grep -i volume" and "pkginfo -l SUNWvolr" to check the version of the Solaris Volume Manager in the Solaris 9 and 10.

The command "nfsstat -a" can be used to find the version of NFS in the Solaris.

The LDoms (Logical Domains) are virtualization and partitioning technology that allows administrators to allocate various resources in the system such as memory, CPUs, and devices into logical groups. This group, then creates multiple, discrete systems, with each having its own operating system resources that are identified within a single computer system.

This technology is used by many enterprises to host multiple instances of Solaris or Linux Virtual Machines on a Sun Server. A Solaris LDoms server has different guest domains and a single control domain for monitoring and reconfiguration of guest domains. Applications are hosted in the guest domains which can be independently powered on or off without affecting other domains. This virtualization technology provides significant cost savings but it also makes the monitoring and management process much more challenging.

The sticky bit in the Solaris is like a permission bit that protects the files within a directory. If a sticky bit is set on the directory, then only a file owner, directory owner, or a privileged user can delete that file. So the sticky bit is used to prevent other users from deleting files in the public directories.

The command "psrinfo | grep memconf" is used to find the size of the RAM installed in the Solaris Server.

The OBP (OpenBoot PROM) provides a list of useful OBP commands. It helps in booting, configuring, and performing diagnostics on the Sun SPARC hardware and clones.

Some of the OBP commands are,

Power-off - it will halt the box and turn off the power.

Reset - it will perform a soft reset. Boot - it boots the system.

.version - it shows the OBP version.

Show-devs - it provides a list of devices available to the system.

Printenv - it is used to get the list of environment variables.

Test somedevice - it is used to perform checks upon the specified device.

You can create a maximum of eight slices per physical disk in the Solaris.

The kstat -p | grep link_ | grep bge command is used to display the network interface variables. You can use the ndd command with it to set network interface configurable to check the current network speed.

NFS daemons are used to handle and support the NFS activities in the Oracle Solaris. Several NFS daemons for handling NFS activities. They are,

Automountd Daemon - It handles the mounting and unmounting request from the autofs service.

Lockd Daemon - It is used to support the record-locking operations on NFS files.

Mountd Daemon - It handles the file-system mount requests from the remote systems. It also provides access control.

Nfs4cbd Daemon - It manages the communication endpoints for the NFS version 4 callback program.

Nfsd Daemon - It handles other client file-system requests.

Nfslogd Daemon - It is used to provide operational logging.

The pkgadd command is used to transfer the content of the software package from the directory or the distribution medium to install it onto the system. It requires some amount of temporary space in the size of the package that is being installed. You can use many options with this command to do specific tasks. The '-d' specifies the device source specifier,'-s' is used to write the package to a spool directory instead of installing it, etc.

The df -k command is used to display the amount of space the is currently in use on each disk mounted on your system. It specifically displays the amount of space available and the percentage of space in use for each disk that is mounted on your system.

//syntax
$ df -k