Interview Questions.

NFS Interview Questions and Answers


NFS Interview Questions and Answers

Q1. What is NFS?

Ans: NFS stands for Network File System. NFS was in the beginning developed by means of Sun Microsystems within the 1980's. NFS allows far off hosts to mount report structures over a network and interact with those report systems as though they're hooked up domestically. This allows system directors to consolidate resources onto centralized servers at the community.

Q2. Why to apply NFS ?

Ans: A Network File System (NFS) permits remote system to mount record systems over a network and interact with those file structures as even though they're hooked up regionally. This allows device administrators to consolidate assets onto centralized servers over the network.

Q3. What is the default port of NFS server ?

Ans: By default NFS uses 2049 TCP port.

Q4. Name of the configuration record for NFS server?

Ans: /etc/exports/

Q5. Which SELinux ports Samaba server works?

Ans: Samba_share_t

Q6. What are extraordinary versions of NFS Server ?

Ans: Currently, there are three versions of NFS. NFS version 2 (NFSv2) is older and widely supported. NFS version three (NFSv3) supports secure asynchronous writes and is extra strong at error managing than NFSv2; it also supports 64-bit record sizes and offsets, allowing clients to get entry to greater than 2Gb of file statistics.

NFS model four (NFSv4) works thru firewalls and at the Internet, now not requires an rpcbind provider, helps ACLs, and utilizes stateful operations. Red Hat Enterprise Linux 6.X & Centos 6.X helps NFSv2,NFSv3, and NFSv4 customers. When mounting a report gadget through NFS, Red Hat Enterprise Linux makes use of NFSv4 via default, if the server helps it.

Q7. What are different alternatives used in /and many others/exports document ?

Ans: Below are list of alternatives used in /and many others/exports report :

ro: The listing is shared examine handiest; the patron machine will no longer be capable of write to it. This is the default.

Rw: The patron system will have examine and write get right of entry to to the listing.

Root_squash: By default, any record request made through user root at the client device is dealt with as if it's miles made by means of person no one on the server. (Exactly which UID the request is mapped to relies upon on the UID of user “no person” on the server, not the client.)

no_root_squash : if this selection is used , then root at the purchaser system will have the equal stage of get admission to to the files at the system as root at the server. This may have severe safety implications, despite the fact that it may be vital in case you want to carry out any administrative paintings at the purchaser gadget that entails the exported directories. You have to no longer specify this feature without a great cause.

No_subtree_check : If only a part of a quantity is exported, a habitual referred to as subtree checking verifies that a file that is requested from the purchaser is in the correct part of the volume. If the whole quantity is exported, disabling this check will speed up transfers.

Sync : Replies to the NFS request handiest after all data has been written to disk. This is a good deal safer than async, and is the default in all nfs-utils variations after 1.0.Zero.

Async : Replies to requests before the data is written to disk. This improves overall performance, but outcomes in lost statistics if the server is going down.

No_wdelay : NFS has an optimization algorithm that delays disk writes if NFS deduces a chance of a related write request quickly arriving. This saves disk writes and might velocity performance

wdelay : Negation of no_wdelay , that is default

nohide : Normally, if a server exports  filesystems one in every of that is installed on the other, then the customer will ought to mount each filesystems explicitly to get get entry to to them. If it simply mounts the parent, it's going to see an empty directory on the location in which the opposite filesystem is mounted. That filesystem is “hidden”. Setting the nohide choice on a filesystem reasons it not to be hidden, and an correctly accredited client can be able to pass from the determine to that filesystem with out noticing the change.

Conceal : Negation of nohide This is the default

Q8. What is portmap?

Ans: The portmapper keeps a listing of what services are walking on what [ports .The listing is used by a connecting device to look what ports it needs to speak to get admission to positive offerings.

Q9. What is SWAT?

Ans: Swat is GUI primarily based administration toll for Samba

Q10. What is the distinction among Hard mount & Soft mount in nfs ?

Ans: Difference between smooth mount and tough mount is indexed underneath :

Soft Mount : Consider we've got set up a NFS proportion the usage of ‘tender mount’ . When a program or application requests a report from the NFS filesystem, NFS purchaser daemons will try to retrieve the records from the NFS server. But, if it doesn’t get any response from the NFS server (due to any crash or failure of NFS server), the NFS customer will file an blunders to the method at the patron machine asking for the document get entry to. The advantage of this mechanism is “fast responsiveness” as it doesn’t await the NFS server to reply. But, the primary drawback of this method is statistics corruption or lack of records. So, this is not a advocated choice to use.

Hard Mount : Suppose we've got set up the NFS proportion the use of difficult mount, it's going to time and again retry to touch the server. Once the server is again on line this system will continue to execute undisturbed from the country where it turned into at some point of server crash. We can use the mount alternative “intr” which lets in NFS requests to be interrupted if the server is going down or can not be reached. Hence the recommended settings are difficult and intr alternatives.

Q11. What is the roles for NTLM?

Ans: The chanllange/repsonse authentication protocol to be had to home windows clients and server for validating connection request.

Q12. What is nbd daemon?

Ans: This daemon handles all call registration and resolution request .It is the primary car involved in network surfing .It handles all UDP primarily based protocol. The nmbd daemon ought to be first command to start as a part of the samba begin up technique.

Q13. On which Ports SAMBA server works?

Ans: UDP port 137 for NetBIOS-ns, NETBIOS name Service

UDP port 138 for netbios-dgm, NetBIOS Datagram service

TCP port 139 for netbios-ssn , NETBIOS session service

TCP port 445 for microsoft-d, Microsoft area carrier

Q14. What do you apprehend by "nfsstat –nfs –server -three" command?

Ans: It will show statistics for NFS version three server.

Q15. Can NFS share set up on Window XP and Justify your answer?

Ans: No, Window XP operating system doesn’t assist nfs protocol.

Q16. How to test nfs server version ?

Ans: ‘nfsstat -o all’ command shows all facts about lively variations of NFS.

Q17. How you'll take a look at "portmap" service is strolling or no longer?

Ans: rpcinfo -p

Q18.  I am not able to mount a NFS percentage. How will you hint out the reason?

Ans: Firstly, take a look at that you have permissions to mount nfs share or no longer. Check /etc/exports record.

Secondly you can get RPC errors: Program Not Registered (or another "RPC" errors)

For this test your NFS server and portmap carrier strolling or no longer by way of "rpcinfo -p"

Q19.  Can I alter export permissions while not having to remount customers a good way to have them take effect?

Ans: Yes. The most secure factor to do is edit /and so on/exports and run "exportfs -r".

Q20. Is rpc.Mountd daemon helps TCP_WRAPPERS?

Ans: Yes, The rpc.Mountd daemon is covered by means of the tcp_wrappers. You have to supply the customers get admission to to rpc.Mountd if they have to be allowed to use NFS Server.