Veritas Volume Manager (VVM or VxVM) Interview Questions & Answers

Question 1. How To Add A Disk To A Disk Group In Veritas Volume Manager?

Answer :

To add the physical disk c0t0d0 in the disk group homedg calling it disk90 in Veritas in Volume Manager:

               # vxdg -g homedg adddisk disk90=c0t0d0

Question 2. How To Remove A Disk From A Disk Group In Veritas Volume Manager?

Answer :

To remove a disk, disk90, from a disk group, homedg, in Veritas Volume Manager:

               # vxdg -g homedg rmdisk disk90

Question 3. How To Clear An Import In Veritas Volume Manager After A Crash?

Answer :

# vxdisk clearimport c0t0d0s0

Question 4. How To List All Disks And Displays Their Status In Vxvm?

Answer :

# vxdisk list

Question 5. How To Remove A Grayed Out Or Obsolete Disk, Or Remove A Disk From A Disk Group In Veritas Volume Manager?

Answer :

# vxdisk rm disk 01

Question 6. How To Remove A Disk So That It Is No Longer Under Veritas Volume Manager Controls?

Answer :

# vxdisk rm c0t0d0

Question 7. How To Add Or Bring A Disk Under Veritas Volume Manager Control?

Answer :

To add or bring a disk under Veritas Volume Manager control:

# vxdiskadd c0t0d1 or # vxdisksetup -i c0t0d1

It might help to newfs the s2 slice of the disk and perform a vxdctl enable to get it to add a disk.

Question 8. How To Remove A Volume And Any Sub Disks And Plexes Associated In Vxvm?

Answer :

# vxedit -rf rm volume name

Question 9. How To Rename The Disk Disk90 To Be Called Disk80 In The Group Rootdg In Veritas Volume Manager?

Answer :

# vxedit -g rootdg rename disk90 disk80

Question 10. How To Set Disk90 In The Group Homedg To Be A Hot Spare In Veritas Volume Manager?

Answer :

# vxedit -g homedg set spare=on disk90

Question 11. How To Set The Comment Field Of Usb Disk Subdisk 01-01 To “comments Are Here”?

Answer :

# vxedit set comment “comments are here” subdisk 01-01

Question 12. How To Sets The User To Ep, The Group To Eigrp And The Mode Rw-rw-rw On The Volume Vg01?

Answer :

# vxedit set user=ip group=eigrp mode=0666 vg01

Question 13. How To Display The Default Disk Group?

Answer :

#vxdg defaults

Question 14. How To Set The Default Disk Group?

Answer :

# vxdctl default

Question 15. How To Display Disk Group Information?

Answer :

# vxdg list or # vxdg list

Question 16. How To Display Free Disk Space In Disk Group?

Answer :

# vxdg free or # vxdg –g free

Question 17. How To Create A Disk Group?

Answer :

# vxdg init cds=on|off

Question 18. How To Create A Disk Group With A Specified Disk Group Version No.?

Answer :

# vxdg –G init

Question 19. How To Make A Non Cds Disk Group To Cds Disk Group Or Vice Versa?

Answer :

# vxdg –g set cds=on|off

Question 20. How To Import A Disk Group?

Answer :

# vxdg import

Question 21. How To Import A Destroyed Disk Group?

Answer :

First you must know the DG ID of the destroyed disk group name. You can get the DG ID by displaying the included disk of destroyed DG.

# vxdg import

Question 22. How To Disable/deport A Disk Group?

Answer :

# vxdg deport

Question 23. How To Rename A Disk Group During Import Operation?

Answer :

# vxdg –t –n import

Question 24. How To Rename A Disk Group During Deport Operation?

Answer :

# vxdg –n deport

Question 25. How To Clear Locks On Disk Group During Import?

Answer :

# vxdg –C import

Question 26. How To Forcible Import The Disk Group?

Answer :

# vxdg –f import

Question 27. How To Move Disk Group Object From One Dg To Another?

Answer :

# vxdg –o expand move

# vxdg –o expand move datadg newdata dg disk01

It will move the entire associated object with disk02 from datadog to new datadog.

Question 28. How To Split A Disk Group To Form A New Disk Group?

Answer :

# vxdg –o expand split disk01 disk02

It will create a new DG with two specified disks.

Question 29. How To Join Two Dgs Into One?

Answer :

# vxdg join

Question 30. How To Destroy A Disk Group?

Answer :

# vxdg destroy

Question 31. How To Upgrade A Disk Group?

Answer :

# vxdg upgrade

It will upgrade the DG to the highest DG version supported by VxVM.

Question 32. Name The Mandatory Disk Group In Vxvm 3.5? How Will You Configure Vxvm In 3.5?

Answer :

Rootvg is the mandatory diskgroup in VxVM 3.5, install is the command to configure VxVM, It will create the disk groups, initializes the disks and adds them to the group.

Question 33. How Will You Create Private And Shared Disk Group Using Vxvm?

Answer :

For Private DG Command: vxdg init

For Shared DG Command: vxdg -s init < disk1 disk2 disk3 >

Question 34. Which Are The Different Layouts For Volumes In Vxvm?

Answer :

Mirror, striped, concat (default one), raid 5, stripe-mirror, mirror-stripe.

Question 35. What Is The Basic Difference Between Private Disk Group And Shared Disk Group?

Answer :

Private DG: The DG which is only visible for the host on which you have created it, if the host is a part of cluster, the private DG will not be visible to the other cluster nodes.

Shared DG: The DG which is shareable and visible to the other cluster nodes.

Question 36. How Will You Add New Disk To The Existing Disk Group?

Answer :

Run vxdisk add command, which will open menu driven program to do various disk operations, select add disks option or you can use another command vxdisk add.

Question 37. How Will You Grow/shrink The Volume/file System? What Is The Meaning Of Grow By And Grow To Options? What Is The Meaning On Shrink To And Shrink By Options?

Answer :

vxassist command is used to do all volume administration; following is the description and syntax.

Grow by option: This is will grow your file system by adding new size to the existing file system.

Grow to option: This will grow your file system as per the new size. This WILL NOT ADD new size to the existing one.

Shrink by option: This will shrink your file system by reducing new size from existing file system.

Shrinkto option: This will shrink your file system as per the new size. This WILL NOT REDUCE the file system by reducing new size.

Command: vxassist -g [growto, growby, shrinkto, shrink by] length

Question 38. How Will You Setup And Unset Up Disks Explicitly Using Vxvm?

Answer :

You can use /etc/vx/bin/vxdisksetup to unset up the disk, and /etc/vx/vxdisksetup to setup the disk.

Question 39. How Will You List The Disks, Which Are In Different Disk Groups?

Answer :

vxdisk list is the command will list the disks from the DG which is currently imported; you can check the same using vxprint command too. Vxdisk -o alldgs list command list all the disks which are in different dg’s.

Question 40. What Is The Private Region In Vxvm?

Answer :

Private region stores the structured VxVM information; it also stores the disk ID and disk geometry. In short words it has metadata of the disk.

Question 41. If, Vxdisk List Command Gives You Disks Status As “error”, What Steps You Will Follow To Make The Respective Disks Online?

Answer :

If you faced this issue because of fabric disconnection then simply do vxdisk scandisks, otherwise unset up the disk using /etc/vx/bin/vxdisksetup and setup the disks again using /etc/vx/bin/vxdisksetup, this will definitely help! [ /etc/vx/bin/vxdisksetup will remove the private region from the disk and destroys data, backup the data before using this option]

Question 42. Can You Reduce A Fs In Vxvm? What Is The Risk Involved?

Answer :

There are a few risks and issues involved while reducing a Filesystem in VxVM.

• UFS volumes cannot be shrunk, only grow operation is permitted.
• VxFS volumes must be mounted for grow and shrink operation; if it is unmounted no operation can be performed
• You cannot resize a volume that contains plexes with different layout types (e.g concat and stripe). Attempting to do so results in the following error message:

              VxVM vxresize ERROR V-5-1-2536 Volume has different

               Organization in each mirror 

To resize such a volume successfully, you must first reconfigure it so that each data plex has the same layout type.

Question 43. What Is The Role Of Vxconfigd Daemon?

Answer :

• Vxconfigd daemon handles all configuration management tasks for VxVM objects. It maintains disk and disk group configuration details, communicates configuration changes to the kernel, and modifies the persistent configuration information stored on disks.
• Vxconfigd provides the interface between VxVM commands and the kernel device drivers.
• Vxconfigd handles   configuration change requests from VxVM utilities, communicates the change requests to the VxVM kernel, and modifies configuration information stored on disk.
• Vxconfigd also initializes VxVM when the system is booted.
• So practically any command which changes the configuration of VxVM objects (plexes, volumes) interact with vxconfigd daemon.

Question 44. Where Is The Diskgroup Configuration Information Is Stored In Vxvm?

Answer :

The DG configuration info is stored in /etc/vx/cbr/bk directory. Last 5 configuration changes are stored.

Question 45. What Is Stored In Problem Of A Vxvm Disk? Do All The Disks Of A Diskgroup Have The Same Information In Their Private Region?

Answer :

The private region of a VxVM disk stored disk header label and configuration information about VxVM objects such as volumes, plexes and sub disks.

Yes, each disk in a diskgroup stores an entire copy of the configuration information.

Question 46. Can You Import A Dg With Incomplete Set Of Disks?

Answer :

Yes, If some of the disks in a Diskgroup have failed, you can import the DG using –f option 

# Vxdg –c import diskgroup

Question 47. How Will You Replace A Faulty Disk In Vxvm?

Answer :

A disk which has failed can be seen from the output of vxdisk list command. The disk device ctd will be missing from the output and it can be seen as failed was: c#t#d#. This confirms that the disk has indeed failed.

We can use vxdiskadd menu options to replace the faulted disk. Choose option 5 from the men, and then list the failed disk using ‘list’ option. We would have to choose an alternate disk for the replacement. The list of available disks is also shown by vxdiskadd. Press ‘y’ and complete the replacement activity.