VMware Interview Question & Answer
how they work..
2.what is ballooning
3.Which driver handles the ballooning
Answers:‐
1.The ESX kernel uses transparent page sharing, ballooning and swapping to reclaim memory.
Ballooning and swapping are used only when the host is running out of machine memory or a
VM limit is hit
2.When the ESX host’s machine memory is scarce or when a VM hits a Limit, The kernel needs
to reclaim memory and prefers ballooning over swapping. The balloon driver is installed inside
the guest OS as part of the VMware Tools installation and is also known as the vmmemctl driver.
When the ESX kernel wants to reclaim memory, it instructs the balloon driver to inflate. The
balloon driver then requests memory from the guest OS. When there is enough memory
available, the guest OS will return memory from its “free” list. When there isn’t enough
memory, the guest OS will have to use its own memory management techniques to decide
which particular pages to reclaim and if necessary page them out to its swap‐ or page‐file.
In the background, the ESX kernel frees up the machine memory page that corresponds to the
physical machine memory page allocated to the balloon driver. When there is enough memory
reclaimed, the balloon driver will deflate after some time returning physical memory pages to
the guest OS again.
This process will also decrease the Host Memory Usage parameter
Ballooning is only effective it the guest has available space in its swap‐ or page‐file, because
used memory pages need to be swapped out in order to allocated the page to the balloon
driver. Ballooning can lead to high guest memory swapping. This is guest OS swapping inside
the VM and is not to be confused with ESX host swapping
3.Vmmemctl driver
New VMware Interview Questions
1. Explain about your production environment? How many clusters, ESX, Data Centres, H/w etc?
2. How does VMotion works? What’s the port number used for it?
3. Prerequisites for VMotion
4. Prerequisites for HA?
5. How do DRS works? Which technology used? What are the priority counts to migrate the VM’s?
6. How does snap shot’s works?
7. What are the files will be created while creating a VM and after powering on the VM?
8. If the VMDK header file corrupt what will happen? How do you troubleshoot?
9. What are the prerequisites for installing VC and Update manager?
10. Have you ever patched the ESX host? What are the steps involved in that?
11. I turned on Maintenance mode in an ESX host, all the VM’s has been migrated to another host, but only one VM failed to migrate? What are the possible reasons?
12. How will you turn start / stop a VM through command prompt?
13. I have upgraded a VM from 4 to 8 GB RAM; it’s getting failed at 90% of powering on? How do you troubleshoot?
14. Storage team provided the new LUN ID to you? How will you configure the LUN in VC? What would be the block size (say for 500 GB volume size)?
15. I want to add a new VLAN to the production network? What are the steps involved in that? And how do you enable it?
16. What’s the difference between Top and ESXTOP command?
17. How will you check the network bandwidth utilization in an ESXS host through command prompt?
18. How will you generate a report for list of ESX, VM’s, RAM and CPU used in your Vsphere environment?
19. What the difference between connecting the ESX host through VC and Vsphere? What are the services involved in that? What are the port numbers’ used?
20. How does FT works? Prerequisites? Port used?
21. Can I VMotion between 2 different data centres? Why?
22. Can I deploy a VM by template in different data centres?
23. I want to increase the system partition size (windows 2003 server- Guest OS) of a VM? How will you do it without any interruption to the end user?
24. Which port number used while 2 ESX transfer the data in between?
25. Unable to connect to a VC through Vsphere client? What could be the reason? How do you troubleshoot?
26. Have you ever upgraded the ESX 3.5 to 4.0? How did you do it?
27. What is AAM? Where is it used? How do you start or stop through command prompt?
28. How will you change the service console IP?
29. What’s the difference between ESX and ESXi?
30. What is the Maximum Virtual SCSI adapters per virtual machine?
31. What is the Maximum Virtual SCSI targets per virtual SCSI adapter?
32. What is the Maximum IDE controllers per virtual machine?
33. What is the Maximum Parallel ports per virtual machine?
